diff --git a/pkgs/io_file/README.md b/pkgs/io_file/README.md
index 30beee01..92ea8b1a 100644
--- a/pkgs/io_file/README.md
+++ b/pkgs/io_file/README.md
@@ -23,7 +23,7 @@ See
 |  enum dir contents    |         |       |       |       |         |            |              |
 |  exists               |         |       |       |       |         |            |              |
 |  get metadata (stat)  |         |       |       |       |         |            |              |
-|  identity (same file) |         |       |       |       |         |            |              |
+|  identity (same file) |         |   ✓   |   ✓   |   ✓   |         |            |              |
 |  open                 |         |       |       |       |         |            |              |
 |  read file (bytes)    |         |   ✓   |   ✓   |   ✓   |    ✓    |            |              |
 |  read file (lines)    |         |       |       |       |         |            |              |
diff --git a/pkgs/io_file/lib/src/file_system.dart b/pkgs/io_file/lib/src/file_system.dart
index 15ad1346..aa16b51b 100644
--- a/pkgs/io_file/lib/src/file_system.dart
+++ b/pkgs/io_file/lib/src/file_system.dart
@@ -34,6 +34,17 @@ class WriteMode {
 
 /// An abstract representation of a file system.
 base class FileSystem {
+  /// Checks whether two paths refer to the same object in the file system.
+  ///
+  /// Throws `PathNotFoundException` if either path doesn't exist.
+  ///
+  /// Links are resolved before determining if the paths refer to the same
+  /// object. Throws `PathNotFoundException` if either path requires resolving
+  /// a broken link.
+  bool same(String path1, String path2) {
+    throw UnsupportedError('same');
+  }
+
   /// Create a directory at the given path.
   ///
   /// If the directory already exists, then `PathExistsException` is thrown.
diff --git a/pkgs/io_file/lib/src/vm_posix_file_system.dart b/pkgs/io_file/lib/src/vm_posix_file_system.dart
index a419728a..feab560e 100644
--- a/pkgs/io_file/lib/src/vm_posix_file_system.dart
+++ b/pkgs/io_file/lib/src/vm_posix_file_system.dart
@@ -60,6 +60,23 @@ external int write(int fd, Pointer<Uint8> buf, int count);
 /// A [FileSystem] implementation for POSIX systems (e.g. Android, iOS, Linux,
 /// macOS).
 base class PosixFileSystem extends FileSystem {
+  @override
+  bool same(String path1, String path2) {
+    final stat1 = stdlibc.stat(path1);
+    if (stat1 == null) {
+      final errno = stdlibc.errno;
+      throw _getError(errno, 'stat failed', path1);
+    }
+
+    final stat2 = stdlibc.stat(path2);
+    if (stat2 == null) {
+      final errno = stdlibc.errno;
+      throw _getError(errno, 'stat failed', path2);
+    }
+
+    return (stat1.st_ino == stat2.st_ino) && (stat1.st_dev == stat2.st_dev);
+  }
+
   @override
   void createDirectory(String path) {
     if (stdlibc.mkdir(path, _defaultDirectoryMode) == -1) {
diff --git a/pkgs/io_file/test/same_test.dart b/pkgs/io_file/test/same_test.dart
new file mode 100644
index 00000000..c7082e32
--- /dev/null
+++ b/pkgs/io_file/test/same_test.dart
@@ -0,0 +1,232 @@
+// Copyright (c) 2025, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+@TestOn('posix')
+library;
+
+import 'dart:io';
+
+import 'package:io_file/io_file.dart';
+import 'package:stdlibc/stdlibc.dart' as stdlibc;
+import 'package:test/test.dart';
+
+import 'test_utils.dart';
+
+void main() {
+  group('same', () {
+    late String tmp;
+    late Directory cwd;
+
+    setUp(() {
+      tmp = createTemp('same');
+      cwd = Directory.current;
+    });
+
+    tearDown(() {
+      Directory.current = cwd;
+      deleteTemp(tmp);
+    });
+
+    //TODO(brianquinlan): test with a very long path.
+
+    test('path1 does not exist', () {
+      final path1 = '$tmp/file1';
+      final path2 = '$tmp/file2';
+      File(path2).writeAsStringSync('Hello World');
+
+      expect(
+        () => fileSystem.same(path1, path2),
+        throwsA(
+          isA<PathNotFoundException>()
+              .having((e) => e.message, 'message', 'stat failed')
+              .having((e) => e.path, 'path', path1)
+              .having((e) => e.osError?.errorCode, 'errorCode', stdlibc.ENOENT),
+        ),
+      );
+    });
+
+    test('path2 does not exist', () {
+      final path1 = '$tmp/file1';
+      final path2 = '$tmp/file2';
+      File(path1).writeAsStringSync('Hello World');
+
+      expect(
+        () => fileSystem.same(path1, path2),
+        throwsA(
+          isA<PathNotFoundException>()
+              .having((e) => e.message, 'message', 'stat failed')
+              .having((e) => e.path, 'path', path2)
+              .having((e) => e.osError?.errorCode, 'errorCode', stdlibc.ENOENT),
+        ),
+      );
+    });
+
+    test('path1 and path2 same, do not exist', () {
+      final path1 = '$tmp/file1';
+      final path2 = '$tmp/file1';
+
+      expect(
+        () => fileSystem.same(path1, path2),
+        throwsA(
+          isA<PathNotFoundException>()
+              .having((e) => e.message, 'message', 'stat failed')
+              .having((e) => e.path, 'path', path1)
+              .having((e) => e.osError?.errorCode, 'errorCode', stdlibc.ENOENT),
+        ),
+      );
+    });
+
+    test('path1 is a broken symlink', () {
+      final path1 = '$tmp/file1';
+      final path2 = '$tmp/file2';
+      Link(path1).createSync('$tmp/file3');
+      File(path2).writeAsStringSync('Hello World');
+
+      expect(
+        () => fileSystem.same(path1, path2),
+        throwsA(
+          isA<PathNotFoundException>()
+              .having((e) => e.message, 'message', 'stat failed')
+              .having((e) => e.path, 'path', path1)
+              .having((e) => e.osError?.errorCode, 'errorCode', stdlibc.ENOENT),
+        ),
+      );
+    });
+
+    test('path2 is a broken symlink', () {
+      final path1 = '$tmp/file1';
+      final path2 = '$tmp/file2';
+      File(path1).writeAsStringSync('Hello World');
+      Link(path2).createSync('$tmp/file3');
+
+      expect(
+        () => fileSystem.same(path1, path2),
+        throwsA(
+          isA<PathNotFoundException>()
+              .having((e) => e.message, 'message', 'stat failed')
+              .having((e) => e.path, 'path', path2)
+              .having((e) => e.osError?.errorCode, 'errorCode', stdlibc.ENOENT),
+        ),
+      );
+    });
+
+    test('path1 and path2 same, broken symlinks', () {
+      final path1 = '$tmp/file1';
+      final path2 = '$tmp/file1';
+      Link(path1).createSync('$tmp/file3');
+
+      expect(
+        () => fileSystem.same(path1, path2),
+        throwsA(
+          isA<PathNotFoundException>()
+              .having((e) => e.message, 'message', 'stat failed')
+              .having((e) => e.path, 'path', path1)
+              .having((e) => e.osError?.errorCode, 'errorCode', stdlibc.ENOENT),
+        ),
+      );
+    });
+
+    test('different files, same content', () {
+      final path1 = '$tmp/file1';
+      final path2 = '$tmp/file2';
+      File(path1).writeAsStringSync('Hello World');
+      File(path2).writeAsStringSync('Hello World');
+
+      expect(fileSystem.same(path1, path2), isFalse);
+    });
+
+    test('same file, absolute and relative paths', () {
+      Directory.current = tmp;
+      final path1 = '$tmp/file1';
+      const path2 = 'file1';
+      File(path1).writeAsStringSync('Hello World');
+
+      expect(fileSystem.same(path1, path2), isTrue);
+    });
+
+    test('file path1, symlink path2', () {
+      final path1 = '$tmp/file1';
+      final path2 = '$tmp/file2';
+      File(path1).writeAsStringSync('Hello World');
+      Link(path2).createSync(path1);
+
+      expect(fileSystem.same(path1, path2), isTrue);
+    });
+
+    test('file symlink path1, symlink path2', () {
+      final path1 = '$tmp/file1';
+      final path2 = '$tmp/file2';
+      File('$tmp/file3').writeAsStringSync('Hello World');
+      Link(path1).createSync('$tmp/file3');
+      Link(path2).createSync('$tmp/file3');
+
+      expect(fileSystem.same(path1, path2), isTrue);
+    });
+
+    test('files through intermediate symlinks', () {
+      Directory('$tmp/subdir').createSync();
+      Link('$tmp/link-to-subdir').createSync('$tmp/subdir');
+      final path1 = '$tmp/subdir/file1';
+      final path2 = '$tmp/link-to-subdir/file1';
+      File(path1).writeAsStringSync('Hello World');
+
+      expect(fileSystem.same(path1, path2), isTrue);
+    });
+
+    test('hard links to same file', () {
+      final path1 = '$tmp/file1';
+      final path2 = '$tmp/file2';
+      File(path1).writeAsStringSync('Hello World');
+      stdlibc.link(path1, path2);
+      expect(fileSystem.same(path1, path2), isTrue);
+    });
+
+    test('different directories, same content', () {
+      final path1 = '$tmp/dir1';
+      final path2 = '$tmp/dir2';
+      Directory(path1).createSync();
+      Directory(path2).createSync();
+
+      expect(fileSystem.same(path1, path2), isFalse);
+    });
+
+    test('same directory, absolute and relative paths', () {
+      Directory.current = tmp;
+      final path1 = '$tmp/dir1';
+      const path2 = 'dir1';
+      Directory(path1).createSync();
+
+      expect(fileSystem.same(path1, path2), isTrue);
+    });
+
+    test('directory path1, symlink path2', () {
+      final path1 = '$tmp/dir1';
+      final path2 = '$tmp/dir2';
+      Directory(path1).createSync();
+      Link(path2).createSync(path1);
+
+      expect(fileSystem.same(path1, path2), isTrue);
+    });
+
+    test('directory symlink path1, symlink path2', () {
+      final path1 = '$tmp/dir1';
+      final path2 = '$tmp/dir2';
+      Directory('$tmp/dir3').createSync();
+      Link(path1).createSync('$tmp/dir3');
+      Link(path2).createSync('$tmp/dir3');
+
+      expect(fileSystem.same(path1, path2), isTrue);
+    });
+
+    test('directories through intermediate symlinks', () {
+      Directory('$tmp/subdir').createSync();
+      Link('$tmp/link-to-subdir').createSync('$tmp/subdir');
+      final path1 = '$tmp/subdir/dir1';
+      final path2 = '$tmp/link-to-subdir/dir1';
+      Directory(path1).createSync();
+
+      expect(fileSystem.same(path1, path2), isTrue);
+    });
+  });
+}