diff --git a/src/git.ts b/src/git.ts
index 5aee49f..84b1587 100644
--- a/src/git.ts
+++ b/src/git.ts
@@ -50,6 +50,15 @@ export async function createWorktree(branch: string, worktreePath: string, cwd:
 
   let result
   if (exists === "local") {
+    // If the branch is checked out in the main worktree, switch it to main first
+    const current = await $`git -C ${cwd} rev-parse --abbrev-ref HEAD`.nothrow().quiet().text()
+    if (current.trim() === branch) {
+      const main = await mainBranch(cwd)
+      const sw = await $`git -C ${cwd} checkout ${main}`.nothrow().quiet()
+      if (sw.exitCode !== 0) {
+        throw new Error(`Cannot move "${cwd}" off branch "${branch}": ${sw.stderr.toString().trim()}`)
+      }
+    }
     result = await $`git worktree add ${worktreePath} ${branch}`.cwd(cwd).nothrow().quiet()
   } else if (exists === "remote") {
     result = await $`git worktree add ${worktreePath} -b ${branch} origin/${branch}`.cwd(cwd).nothrow().quiet()