diff --git a/doc/api/stream_iter.md b/doc/api/stream_iter.md
index aa96ce02813..e2f30ce6a94 100644
--- a/doc/api/stream_iter.md
+++ b/doc/api/stream_iter.md
@@ -714,7 +714,7 @@ added:
 
 * `source` {Iterable} The sync data source.
 * `...transforms` {Function|Object} Zero or more sync transforms.
-* `writer` {Object} Destination with `write(chunk)` method.
+* `writer` {Object} Destination with a `writeSync(chunk)` method.
 * `options` {Object}
   * `failOnIncompleteClose` {boolean} If `true`, call `writer.fail()` when
     `writer.endSync()` cannot close the writer synchronously. Ignored when
@@ -727,8 +727,11 @@ added:
 Synchronous version of [`pipeTo()`][]. The `source`, all transforms, and the
 `writer` must be synchronous. Cannot accept async iterables or promises.
 
-The `writer` must have the `*Sync` methods (`writeSync`, `writevSync`,
-`endSync`) and `fail()` for this to work.
+The `writer` must have a `writeSync()` method. The other methods are
+optional: `writevSync()` is used for batches of more than one chunk if it is
+present, `endSync()` is called to close the writer (unless `preventClose` is
+`true`), and `fail()` is called if the pipe fails (unless `preventFail` is
+`true`). A writer without `endSync()` is not closed.
 
 `pipeToSync()` never falls back to the asynchronous writer methods. If
 `writer.endSync()` returns `-1` because the writer cannot close synchronously
diff --git a/lib/internal/streams/iter/pull.js b/lib/internal/streams/iter/pull.js
index 6dff97e42be..70e89a99423 100644
--- a/lib/internal/streams/iter/pull.js
+++ b/lib/internal/streams/iter/pull.js
@@ -1032,12 +1032,9 @@ function pipeToSync(source, ...args) {
     context: 'options',
   });
   const hasWritevSync = typeof writer.writevSync === 'function';
+  // endSync() is optional: a writer without it is not closed.
   const endSync = writer.endSync;
-
-  if (!options.preventClose && typeof endSync !== 'function') {
-    throw new ERR_INVALID_ARG_TYPE(
-      'writer.endSync', 'Function', endSync);
-  }
+  const hasEndSync = typeof endSync === 'function';
 
   // Normalize source and create pipeline
   const normalized = fromSync(source);
@@ -1074,7 +1071,7 @@ function pipeToSync(source, ...args) {
       }
     }
 
-    if (!options.preventClose) {
+    if (!options.preventClose && hasEndSync) {
       closedSync = FunctionPrototypeCall(endSync, writer) >= 0;
     }
   } catch (error) {
diff --git a/test/parallel/test-stream-iter-pipeto-edge.js b/test/parallel/test-stream-iter-pipeto-edge.js
index 0c5448db5a8..082871a9e4c 100644
--- a/test/parallel/test-stream-iter-pipeto-edge.js
+++ b/test/parallel/test-stream-iter-pipeto-edge.js
@@ -47,20 +47,18 @@ async function testPipeToSyncEndSyncFailureDoesNotFailWriter() {
   assert.strictEqual(await result, 'abcdef');
 }
 
-// pipeToSync requires endSync() when closing is enabled.
+// pipeToSync does not require endSync().
 async function testPipeToSyncNoEndSync() {
-  let writeCalled = false;
-  let endCalled = false;
+  // endSync() is optional. Without it the data is still written and the
+  // writer is not closed; pipeToSync() never falls back to end().
+  const written = [];
   const writer = {
-    writeSync() { writeCalled = true; return true; },
-    end() { endCalled = true; },
+    writeSync(chunk) { written.push(chunk); return true; },
+    end: common.mustNotCall(),
+    fail: common.mustNotCall(),
   };
-  assert.throws(
-    () => pipeToSync(fromSync('data'), writer),
-    { code: 'ERR_INVALID_ARG_TYPE' },
-  );
-  assert.strictEqual(writeCalled, false);
-  assert.strictEqual(endCalled, false);
+  assert.strictEqual(pipeToSync(fromSync('data'), writer), 4);
+  assert.deepStrictEqual(written, [new TextEncoder().encode('data')]);
 }
 
 // pipeToSync with preventFail: true — source error does NOT call fail()