diff --git a/crates/wasi-common/cap-std-sync/src/dir.rs b/crates/wasi-common/cap-std-sync/src/dir.rs
index 2552787900..13e8391452 100644
--- a/crates/wasi-common/cap-std-sync/src/dir.rs
+++ b/crates/wasi-common/cap-std-sync/src/dir.rs
@@ -17,11 +17,12 @@ impl Dir {
     }
 }
 
+#[wiggle::async_trait]
 impl WasiDir for Dir {
     fn as_any(&self) -> &dyn Any {
         self
     }
-    fn open_file(
+    async fn open_file(
         &self,
         symlink_follow: bool,
         path: &str,
@@ -84,7 +85,7 @@ impl WasiDir for Dir {
         Ok(Box::new(File::from_cap_std(f)))
     }
 
-    fn open_dir(&self, symlink_follow: bool, path: &str) -> Result<Box<dyn WasiDir>, Error> {
+    async fn open_dir(&self, symlink_follow: bool, path: &str) -> Result<Box<dyn WasiDir>, Error> {
         let d = if symlink_follow {
             self.0.open_dir(Path::new(path))?
         } else {
@@ -93,11 +94,11 @@ impl WasiDir for Dir {
         Ok(Box::new(Dir::from_cap_std(d)))
     }
 
-    fn create_dir(&self, path: &str) -> Result<(), Error> {
+    async fn create_dir(&self, path: &str) -> Result<(), Error> {
         self.0.create_dir(Path::new(path))?;
         Ok(())
     }
-    fn readdir(
+    async fn readdir(
         &self,
         cursor: ReaddirCursor,
     ) -> Result<Box<dyn Iterator<Item = Result<ReaddirEntity, Error>>>, Error> {
@@ -146,24 +147,24 @@ impl WasiDir for Dir {
         Ok(Box::new(rd))
     }
 
-    fn symlink(&self, src_path: &str, dest_path: &str) -> Result<(), Error> {
+    async fn symlink(&self, src_path: &str, dest_path: &str) -> Result<(), Error> {
         self.0.symlink(src_path, dest_path)?;
         Ok(())
     }
-    fn remove_dir(&self, path: &str) -> Result<(), Error> {
+    async fn remove_dir(&self, path: &str) -> Result<(), Error> {
         self.0.remove_dir(Path::new(path))?;
         Ok(())
     }
 
-    fn unlink_file(&self, path: &str) -> Result<(), Error> {
+    async fn unlink_file(&self, path: &str) -> Result<(), Error> {
         self.0.remove_file_or_symlink(Path::new(path))?;
         Ok(())
     }
-    fn read_link(&self, path: &str) -> Result<PathBuf, Error> {
+    async fn read_link(&self, path: &str) -> Result<PathBuf, Error> {
         let link = self.0.read_link(Path::new(path))?;
         Ok(link)
     }
-    fn get_filestat(&self) -> Result<Filestat, Error> {
+    async fn get_filestat(&self) -> Result<Filestat, Error> {
         let meta = self.0.dir_metadata()?;
         Ok(Filestat {
             device_id: meta.dev(),
@@ -176,7 +177,11 @@ impl WasiDir for Dir {
             ctim: meta.created().map(|t| Some(t.into_std())).unwrap_or(None),
         })
     }
-    fn get_path_filestat(&self, path: &str, follow_symlinks: bool) -> Result<Filestat, Error> {
+    async fn get_path_filestat(
+        &self,
+        path: &str,
+        follow_symlinks: bool,
+    ) -> Result<Filestat, Error> {
         let meta = if follow_symlinks {
             self.0.metadata(Path::new(path))?
         } else {
@@ -193,7 +198,12 @@ impl WasiDir for Dir {
             ctim: meta.created().map(|t| Some(t.into_std())).unwrap_or(None),
         })
     }
-    fn rename(&self, src_path: &str, dest_dir: &dyn WasiDir, dest_path: &str) -> Result<(), Error> {
+    async fn rename(
+        &self,
+        src_path: &str,
+        dest_dir: &dyn WasiDir,
+        dest_path: &str,
+    ) -> Result<(), Error> {
         let dest_dir = dest_dir
             .as_any()
             .downcast_ref::<Self>()
@@ -202,7 +212,7 @@ impl WasiDir for Dir {
             .rename(Path::new(src_path), &dest_dir.0, Path::new(dest_path))?;
         Ok(())
     }
-    fn hard_link(
+    async fn hard_link(
         &self,
         src_path: &str,
         target_dir: &dyn WasiDir,
@@ -217,7 +227,7 @@ impl WasiDir for Dir {
         self.0.hard_link(src_path, &target_dir.0, target_path)?;
         Ok(())
     }
-    fn set_times(
+    async fn set_times(
         &self,
         path: &str,
         atime: Option<wasi_common::SystemTimeSpec>,
@@ -261,7 +271,7 @@ mod test {
         let preopen_dir = unsafe { cap_std::fs::Dir::open_ambient_dir(tempdir.path()) }
             .expect("open ambient temporary dir");
         let preopen_dir = Dir::from_cap_std(preopen_dir);
-        wasi_common::WasiDir::open_dir(&preopen_dir, false, ".")
+        run(wasi_common::WasiDir::open_dir(&preopen_dir, false, "."))
             .expect("open the same directory via WasiDir abstraction");
     }
 
@@ -275,9 +285,8 @@ mod test {
 
         fn readdir_into_map(dir: &dyn WasiDir) -> HashMap<String, ReaddirEntity> {
             let mut out = HashMap::new();
-            for readdir_result in dir
-                .readdir(ReaddirCursor::from(0))
-                .expect("readdir succeeds")
+            for readdir_result in
+                run(dir.readdir(ReaddirCursor::from(0))).expect("readdir succeeds")
             {
                 let entity = readdir_result.expect("readdir entry is valid");
                 out.insert(entity.name.clone(), entity);
@@ -303,16 +312,15 @@ mod test {
         assert!(entities.get(".").is_some());
         assert!(entities.get("..").is_some());
 
-        preopen_dir
-            .open_file(
-                false,
-                "file1",
-                OFlags::CREATE,
-                true,
-                false,
-                FdFlags::empty(),
-            )
-            .expect("create file1");
+        run(preopen_dir.open_file(
+            false,
+            "file1",
+            OFlags::CREATE,
+            true,
+            false,
+            FdFlags::empty(),
+        ))
+        .expect("create file1");
 
         let entities = readdir_into_map(&preopen_dir);
         assert_eq!(entities.len(), 3, "should be ., .., file1 {:?}", entities);
@@ -329,4 +337,41 @@ mod test {
             FileType::RegularFile
         );
     }
+
+    fn run<F: std::future::Future>(future: F) -> F::Output {
+        use std::pin::Pin;
+        use std::task::{Context, Poll, RawWaker, RawWakerVTable, Waker};
+
+        let mut f = Pin::from(Box::new(future));
+        let waker = dummy_waker();
+        let mut cx = Context::from_waker(&waker);
+        match f.as_mut().poll(&mut cx) {
+            Poll::Ready(val) => return val,
+            Poll::Pending => {
+                panic!("Cannot wait on pending future: must enable wiggle \"async\" future and execute on an async Store")
+            }
+        }
+
+        fn dummy_waker() -> Waker {
+            return unsafe { Waker::from_raw(clone(5 as *const _)) };
+
+            unsafe fn clone(ptr: *const ()) -> RawWaker {
+                assert_eq!(ptr as usize, 5);
+                const VTABLE: RawWakerVTable = RawWakerVTable::new(clone, wake, wake_by_ref, drop);
+                RawWaker::new(ptr, &VTABLE)
+            }
+
+            unsafe fn wake(ptr: *const ()) {
+                assert_eq!(ptr as usize, 5);
+            }
+
+            unsafe fn wake_by_ref(ptr: *const ()) {
+                assert_eq!(ptr as usize, 5);
+            }
+
+            unsafe fn drop(ptr: *const ()) {
+                assert_eq!(ptr as usize, 5);
+            }
+        }
+    }
 }
diff --git a/crates/wasi-common/cap-std-sync/src/file.rs b/crates/wasi-common/cap-std-sync/src/file.rs
index f89a090ea1..ba9ff2743a 100644
--- a/crates/wasi-common/cap-std-sync/src/file.rs
+++ b/crates/wasi-common/cap-std-sync/src/file.rs
@@ -20,27 +20,28 @@ impl File {
     }
 }
 
+#[wiggle::async_trait]
 impl WasiFile for File {
     fn as_any(&self) -> &dyn Any {
         self
     }
-    fn datasync(&self) -> Result<(), Error> {
+    async fn datasync(&self) -> Result<(), Error> {
         self.0.sync_data()?;
         Ok(())
     }
-    fn sync(&self) -> Result<(), Error> {
+    async fn sync(&self) -> Result<(), Error> {
         self.0.sync_all()?;
         Ok(())
     }
-    fn get_filetype(&self) -> Result<FileType, Error> {
+    async fn get_filetype(&self) -> Result<FileType, Error> {
         let meta = self.0.metadata()?;
         Ok(filetype_from(&meta.file_type()))
     }
-    fn get_fdflags(&self) -> Result<FdFlags, Error> {
+    async fn get_fdflags(&self) -> Result<FdFlags, Error> {
         let fdflags = self.0.get_fd_flags()?;
         Ok(from_sysif_fdflags(fdflags))
     }
-    fn set_fdflags(&mut self, fdflags: FdFlags) -> Result<(), Error> {
+    async fn set_fdflags(&mut self, fdflags: FdFlags) -> Result<(), Error> {
         if fdflags.intersects(
             wasi_common::file::FdFlags::DSYNC
                 | wasi_common::file::FdFlags::SYNC
@@ -50,7 +51,7 @@ impl WasiFile for File {
         }
         Ok(self.0.set_fd_flags(to_sysif_fdflags(fdflags))?)
     }
-    fn get_filestat(&self) -> Result<Filestat, Error> {
+    async fn get_filestat(&self) -> Result<Filestat, Error> {
         let meta = self.0.metadata()?;
         Ok(Filestat {
             device_id: meta.dev(),
@@ -63,19 +64,19 @@ impl WasiFile for File {
             ctim: meta.created().map(|t| Some(t.into_std())).unwrap_or(None),
         })
     }
-    fn set_filestat_size(&self, size: u64) -> Result<(), Error> {
+    async fn set_filestat_size(&self, size: u64) -> Result<(), Error> {
         self.0.set_len(size)?;
         Ok(())
     }
-    fn advise(&self, offset: u64, len: u64, advice: Advice) -> Result<(), Error> {
+    async fn advise(&self, offset: u64, len: u64, advice: Advice) -> Result<(), Error> {
         self.0.advise(offset, len, convert_advice(advice))?;
         Ok(())
     }
-    fn allocate(&self, offset: u64, len: u64) -> Result<(), Error> {
+    async fn allocate(&self, offset: u64, len: u64) -> Result<(), Error> {
         self.0.allocate(offset, len)?;
         Ok(())
     }
-    fn set_times(
+    async fn set_times(
         &self,
         atime: Option<wasi_common::SystemTimeSpec>,
         mtime: Option<wasi_common::SystemTimeSpec>,
@@ -84,30 +85,38 @@ impl WasiFile for File {
             .set_times(convert_systimespec(atime), convert_systimespec(mtime))?;
         Ok(())
     }
-    fn read_vectored(&self, bufs: &mut [io::IoSliceMut]) -> Result<u64, Error> {
+    async fn read_vectored<'a>(&self, bufs: &mut [io::IoSliceMut<'a>]) -> Result<u64, Error> {
         let n = self.0.read_vectored(bufs)?;
         Ok(n.try_into()?)
     }
-    fn read_vectored_at(&self, bufs: &mut [io::IoSliceMut], offset: u64) -> Result<u64, Error> {
+    async fn read_vectored_at<'a>(
+        &self,
+        bufs: &mut [io::IoSliceMut<'a>],
+        offset: u64,
+    ) -> Result<u64, Error> {
         let n = self.0.read_vectored_at(bufs, offset)?;
         Ok(n.try_into()?)
     }
-    fn write_vectored(&self, bufs: &[io::IoSlice]) -> Result<u64, Error> {
+    async fn write_vectored<'a>(&self, bufs: &[io::IoSlice<'a>]) -> Result<u64, Error> {
         let n = self.0.write_vectored(bufs)?;
         Ok(n.try_into()?)
     }
-    fn write_vectored_at(&self, bufs: &[io::IoSlice], offset: u64) -> Result<u64, Error> {
+    async fn write_vectored_at<'a>(
+        &self,
+        bufs: &[io::IoSlice<'a>],
+        offset: u64,
+    ) -> Result<u64, Error> {
         let n = self.0.write_vectored_at(bufs, offset)?;
         Ok(n.try_into()?)
     }
-    fn seek(&self, pos: std::io::SeekFrom) -> Result<u64, Error> {
+    async fn seek(&self, pos: std::io::SeekFrom) -> Result<u64, Error> {
         Ok(self.0.seek(pos)?)
     }
-    fn peek(&self, buf: &mut [u8]) -> Result<u64, Error> {
+    async fn peek(&self, buf: &mut [u8]) -> Result<u64, Error> {
         let n = self.0.peek(buf)?;
         Ok(n.try_into()?)
     }
-    fn num_ready_bytes(&self) -> Result<u64, Error> {
+    async fn num_ready_bytes(&self) -> Result<u64, Error> {
         Ok(self.0.num_ready_bytes()?)
     }
 }
diff --git a/crates/wasi-common/cap-std-sync/src/sched/unix.rs b/crates/wasi-common/cap-std-sync/src/sched/unix.rs
index eeb9c9c0a7..37fbbc1c0f 100644
--- a/crates/wasi-common/cap-std-sync/src/sched/unix.rs
+++ b/crates/wasi-common/cap-std-sync/src/sched/unix.rs
@@ -79,7 +79,7 @@ impl WasiSched for SyncSched {
                 if let Some(revents) = pollfd.revents() {
                     let (nbytes, rwsub) = match rwsub {
                         Subscription::Read(sub) => {
-                            let ready = sub.file.num_ready_bytes()?;
+                            let ready = sub.file.num_ready_bytes().await?;
                             (std::cmp::max(ready, 1), sub)
                         }
                         Subscription::Write(sub) => (0, sub),
diff --git a/crates/wasi-common/cap-std-sync/src/stdio.rs b/crates/wasi-common/cap-std-sync/src/stdio.rs
index 92a76d47ff..d4d515cfeb 100644
--- a/crates/wasi-common/cap-std-sync/src/stdio.rs
+++ b/crates/wasi-common/cap-std-sync/src/stdio.rs
@@ -22,31 +22,32 @@ pub fn stdin() -> Stdin {
     Stdin(std::io::stdin())
 }
 
+#[wiggle::async_trait]
 impl WasiFile for Stdin {
     fn as_any(&self) -> &dyn Any {
         self
     }
-    fn datasync(&self) -> Result<(), Error> {
+    async fn datasync(&self) -> Result<(), Error> {
         Ok(())
     }
-    fn sync(&self) -> Result<(), Error> {
+    async fn sync(&self) -> Result<(), Error> {
         Ok(())
     }
-    fn get_filetype(&self) -> Result<FileType, Error> {
+    async fn get_filetype(&self) -> Result<FileType, Error> {
         Ok(FileType::Unknown)
     }
-    fn get_fdflags(&self) -> Result<FdFlags, Error> {
+    async fn get_fdflags(&self) -> Result<FdFlags, Error> {
         Ok(FdFlags::empty())
     }
-    fn set_fdflags(&mut self, _fdflags: FdFlags) -> Result<(), Error> {
+    async fn set_fdflags(&mut self, _fdflags: FdFlags) -> Result<(), Error> {
         Err(Error::badf())
     }
-    fn get_filestat(&self) -> Result<Filestat, Error> {
+    async fn get_filestat(&self) -> Result<Filestat, Error> {
         let meta = self.0.as_file_view().metadata()?;
         Ok(Filestat {
             device_id: 0,
             inode: 0,
-            filetype: self.get_filetype()?,
+            filetype: self.get_filetype().await?,
             nlink: 0,
             size: meta.len(),
             atim: meta.accessed().ok(),
@@ -54,35 +55,43 @@ impl WasiFile for Stdin {
             ctim: meta.created().ok(),
         })
     }
-    fn set_filestat_size(&self, _size: u64) -> Result<(), Error> {
+    async fn set_filestat_size(&self, _size: u64) -> Result<(), Error> {
         Err(Error::badf())
     }
-    fn advise(&self, _offset: u64, _len: u64, _advice: Advice) -> Result<(), Error> {
+    async fn advise(&self, _offset: u64, _len: u64, _advice: Advice) -> Result<(), Error> {
         Err(Error::badf())
     }
-    fn allocate(&self, _offset: u64, _len: u64) -> Result<(), Error> {
+    async fn allocate(&self, _offset: u64, _len: u64) -> Result<(), Error> {
         Err(Error::badf())
     }
-    fn read_vectored(&self, bufs: &mut [io::IoSliceMut]) -> Result<u64, Error> {
+    async fn read_vectored<'a>(&self, bufs: &mut [io::IoSliceMut<'a>]) -> Result<u64, Error> {
         let n = self.0.as_file_view().read_vectored(bufs)?;
         Ok(n.try_into().map_err(|_| Error::range())?)
     }
-    fn read_vectored_at(&self, _bufs: &mut [io::IoSliceMut], _offset: u64) -> Result<u64, Error> {
+    async fn read_vectored_at<'a>(
+        &self,
+        _bufs: &mut [io::IoSliceMut<'a>],
+        _offset: u64,
+    ) -> Result<u64, Error> {
         Err(Error::seek_pipe())
     }
-    fn write_vectored(&self, _bufs: &[io::IoSlice]) -> Result<u64, Error> {
+    async fn write_vectored<'a>(&self, _bufs: &[io::IoSlice<'a>]) -> Result<u64, Error> {
         Err(Error::badf())
     }
-    fn write_vectored_at(&self, _bufs: &[io::IoSlice], _offset: u64) -> Result<u64, Error> {
+    async fn write_vectored_at<'a>(
+        &self,
+        _bufs: &[io::IoSlice<'a>],
+        _offset: u64,
+    ) -> Result<u64, Error> {
         Err(Error::badf())
     }
-    fn seek(&self, _pos: std::io::SeekFrom) -> Result<u64, Error> {
+    async fn seek(&self, _pos: std::io::SeekFrom) -> Result<u64, Error> {
         Err(Error::seek_pipe())
     }
-    fn peek(&self, _buf: &mut [u8]) -> Result<u64, Error> {
+    async fn peek(&self, _buf: &mut [u8]) -> Result<u64, Error> {
         Err(Error::seek_pipe())
     }
-    fn set_times(
+    async fn set_times(
         &self,
         atime: Option<wasi_common::SystemTimeSpec>,
         mtime: Option<wasi_common::SystemTimeSpec>,
@@ -91,7 +100,7 @@ impl WasiFile for Stdin {
             .set_times(convert_systimespec(atime), convert_systimespec(mtime))?;
         Ok(())
     }
-    fn num_ready_bytes(&self) -> Result<u64, Error> {
+    async fn num_ready_bytes(&self) -> Result<u64, Error> {
         Ok(self.0.num_ready_bytes()?)
     }
 }
@@ -110,31 +119,32 @@ impl AsRawFd for Stdin {
 
 macro_rules! wasi_file_write_impl {
     ($ty:ty) => {
+        #[wiggle::async_trait]
         impl WasiFile for $ty {
             fn as_any(&self) -> &dyn Any {
                 self
             }
-            fn datasync(&self) -> Result<(), Error> {
+            async fn datasync(&self) -> Result<(), Error> {
                 Ok(())
             }
-            fn sync(&self) -> Result<(), Error> {
+            async fn sync(&self) -> Result<(), Error> {
                 Ok(())
             }
-            fn get_filetype(&self) -> Result<FileType, Error> {
+            async fn get_filetype(&self) -> Result<FileType, Error> {
                 Ok(FileType::Unknown)
             }
-            fn get_fdflags(&self) -> Result<FdFlags, Error> {
+            async fn get_fdflags(&self) -> Result<FdFlags, Error> {
                 Ok(FdFlags::APPEND)
             }
-            fn set_fdflags(&mut self, _fdflags: FdFlags) -> Result<(), Error> {
+            async fn set_fdflags(&mut self, _fdflags: FdFlags) -> Result<(), Error> {
                 Err(Error::badf())
             }
-            fn get_filestat(&self) -> Result<Filestat, Error> {
+            async fn get_filestat(&self) -> Result<Filestat, Error> {
                 let meta = self.0.as_file_view().metadata()?;
                 Ok(Filestat {
                     device_id: 0,
                     inode: 0,
-                    filetype: self.get_filetype()?,
+                    filetype: self.get_filetype().await?,
                     nlink: 0,
                     size: meta.len(),
                     atim: meta.accessed().ok(),
@@ -142,39 +152,46 @@ macro_rules! wasi_file_write_impl {
                     ctim: meta.created().ok(),
                 })
             }
-            fn set_filestat_size(&self, _size: u64) -> Result<(), Error> {
+            async fn set_filestat_size(&self, _size: u64) -> Result<(), Error> {
                 Err(Error::badf())
             }
-            fn advise(&self, _offset: u64, _len: u64, _advice: Advice) -> Result<(), Error> {
+            async fn advise(&self, _offset: u64, _len: u64, _advice: Advice) -> Result<(), Error> {
                 Err(Error::badf())
             }
-            fn allocate(&self, _offset: u64, _len: u64) -> Result<(), Error> {
+            async fn allocate(&self, _offset: u64, _len: u64) -> Result<(), Error> {
                 Err(Error::badf())
             }
-            fn read_vectored(&self, _bufs: &mut [io::IoSliceMut]) -> Result<u64, Error> {
-                Err(Error::badf())
-            }
-            fn read_vectored_at(
+            async fn read_vectored<'a>(
                 &self,
-                _bufs: &mut [io::IoSliceMut],
+                _bufs: &mut [io::IoSliceMut<'a>],
+            ) -> Result<u64, Error> {
+                Err(Error::badf())
+            }
+            async fn read_vectored_at<'a>(
+                &self,
+                _bufs: &mut [io::IoSliceMut<'a>],
                 _offset: u64,
             ) -> Result<u64, Error> {
                 Err(Error::badf())
             }
-            fn write_vectored(&self, bufs: &[io::IoSlice]) -> Result<u64, Error> {
+            async fn write_vectored<'a>(&self, bufs: &[io::IoSlice<'a>]) -> Result<u64, Error> {
                 let n = self.0.as_file_view().write_vectored(bufs)?;
                 Ok(n.try_into().map_err(|c| Error::range().context(c))?)
             }
-            fn write_vectored_at(&self, _bufs: &[io::IoSlice], _offset: u64) -> Result<u64, Error> {
+            async fn write_vectored_at<'a>(
+                &self,
+                _bufs: &[io::IoSlice<'a>],
+                _offset: u64,
+            ) -> Result<u64, Error> {
                 Err(Error::seek_pipe())
             }
-            fn seek(&self, _pos: std::io::SeekFrom) -> Result<u64, Error> {
+            async fn seek(&self, _pos: std::io::SeekFrom) -> Result<u64, Error> {
                 Err(Error::seek_pipe())
             }
-            fn peek(&self, _buf: &mut [u8]) -> Result<u64, Error> {
+            async fn peek(&self, _buf: &mut [u8]) -> Result<u64, Error> {
                 Err(Error::badf())
             }
-            fn set_times(
+            async fn set_times(
                 &self,
                 atime: Option<wasi_common::SystemTimeSpec>,
                 mtime: Option<wasi_common::SystemTimeSpec>,
@@ -183,7 +200,7 @@ macro_rules! wasi_file_write_impl {
                     .set_times(convert_systimespec(atime), convert_systimespec(mtime))?;
                 Ok(())
             }
-            fn num_ready_bytes(&self) -> Result<u64, Error> {
+            async fn num_ready_bytes(&self) -> Result<u64, Error> {
                 Ok(0)
             }
         }