diff --git a/.devcontainer/Dockerfile b/.devcontainer/Dockerfile
index 9f808af38e69df..365756458bba30 100644
--- a/.devcontainer/Dockerfile
+++ b/.devcontainer/Dockerfile
@@ -6,7 +6,7 @@ ENV WASI_SDK_VERSION=20
 ENV WASI_SDK_PATH=/opt/wasi-sdk
 
 ENV WASMTIME_HOME=/opt/wasmtime
-ENV WASMTIME_VERSION=14.0.4
+ENV WASMTIME_VERSION=18.0.2
 ENV WASMTIME_CPU_ARCH=x86_64
 
 RUN dnf -y --nodocs --setopt=install_weak_deps=False install /usr/bin/{blurb,clang,curl,git,ln,tar,xz} 'dnf-command(builddep)' && \
diff --git a/Misc/NEWS.d/next/Build/2024-03-04-12-43-42.gh-issue-116313.cLLb8S.rst b/Misc/NEWS.d/next/Build/2024-03-04-12-43-42.gh-issue-116313.cLLb8S.rst
new file mode 100644
index 00000000000000..61501549060024
--- /dev/null
+++ b/Misc/NEWS.d/next/Build/2024-03-04-12-43-42.gh-issue-116313.cLLb8S.rst
@@ -0,0 +1 @@
+Get WASI builds to work under wasmtime 18 w/ WASI 0.2/preview2 primitives.
diff --git a/Tools/wasm/wasi.py b/Tools/wasm/wasi.py
index 1e75db5c7b8329..efb005e53ab989 100644
--- a/Tools/wasm/wasi.py
+++ b/Tools/wasm/wasi.py
@@ -283,8 +283,10 @@ def main():
                         # The 8388608 value comes from `ulimit -s` under Linux
                         # which equates to 8291 KiB.
                         "--wasm max-wasm-stack=8388608 "
-                        # Enable thread support.
-                        "--wasm threads=y --wasi threads=y "
+                        # Use WASI 0.2 primitives.
+                        "--wasi preview2 "
+                        # Enable thread support; causes use of preview1.
+                        #"--wasm threads=y --wasi threads=y "
                         # Map the checkout to / to load the stdlib from /Lib.
                         "--dir {HOST_DIR}::{GUEST_DIR} "
                         # Set PYTHONPATH to the sysconfig data.
diff --git a/configure.ac b/configure.ac
index 103c24962b7b42..80d0a7edc7cad4 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1537,7 +1537,7 @@ then
     dnl TODO: support other WASI runtimes
     dnl wasmtime starts the proces with "/" as CWD. For OOT builds add the
     dnl directory containing _sysconfigdata to PYTHONPATH.
-    [WASI/*], [HOSTRUNNER='wasmtime run --env PYTHONPATH=/$(shell realpath --relative-to $(abs_srcdir) $(abs_builddir))/$(shell cat pybuilddir.txt):/Lib --mapdir /::$(srcdir) --'],
+    [WASI/*], [HOSTRUNNER='wasmtime run --wasm max-wasm-stack=8388608 --wasi preview2 --env PYTHONPATH=/$(shell realpath --relative-to $(abs_srcdir) $(abs_builddir))/$(shell cat pybuilddir.txt):/Lib --dir $(srcdir)::/'],
     [HOSTRUNNER='']
   )
 fi