diff --git a/ui/src/components/ConversationDrawer.tsx b/ui/src/components/ConversationDrawer.tsx
index 9165cd687f272e9ce2e6e5a8a49968e8c2426727..d0e84eabc7a54d7820757a436522018ed08f061a 100644
--- a/ui/src/components/ConversationDrawer.tsx
+++ b/ui/src/components/ConversationDrawer.tsx
@@ -172,6 +172,10 @@ function ConversationDrawer({
   };
 
   const handleRenameKeyDown = (e: React.KeyboardEvent, conversationId: string) => {
+    // Don't submit while IME is composing (e.g., converting Japanese hiragana to kanji)
+    if (e.nativeEvent.isComposing) {
+      return;
+    }
     if (e.key === "Enter") {
       e.preventDefault();
       handleRename(conversationId);
diff --git a/ui/src/components/DirectoryPickerModal.tsx b/ui/src/components/DirectoryPickerModal.tsx
index e5ab16ebd71e398bcb4cda66326d601ed3646011..966c762e66e05fb9e9868d44bcd76fea2ea0e897 100644
--- a/ui/src/components/DirectoryPickerModal.tsx
+++ b/ui/src/components/DirectoryPickerModal.tsx
@@ -172,6 +172,10 @@ function DirectoryPickerModal({
   };
 
   const handleInputKeyDown = (e: React.KeyboardEvent<HTMLInputElement>) => {
+    // Don't submit while IME is composing (e.g., converting Japanese hiragana to kanji)
+    if (e.nativeEvent.isComposing) {
+      return;
+    }
     if (e.key === "Enter") {
       e.preventDefault();
       handleSelect();
diff --git a/ui/src/components/MessageInput.tsx b/ui/src/components/MessageInput.tsx
index f0e5b750c58d4ac0942e36463b0617ec0535a63e..41209d9ea7e9cf163c5b87dc5fe9783c4fed663f 100644
--- a/ui/src/components/MessageInput.tsx
+++ b/ui/src/components/MessageInput.tsx
@@ -304,6 +304,10 @@ function MessageInput({
   };
 
   const handleKeyDown = (e: React.KeyboardEvent) => {
+    // Don't submit while IME is composing (e.g., converting Japanese hiragana to kanji)
+    if (e.nativeEvent.isComposing) {
+      return;
+    }
     if (e.key === "Enter" && !e.shiftKey) {
       e.preventDefault();
       handleSubmit(e);