diff --git a/src/mudlib/commands/build.py b/src/mudlib/commands/build.py
index 6adc300..d31ae8d 100644
--- a/src/mudlib/commands/build.py
+++ b/src/mudlib/commands/build.py
@@ -8,7 +8,7 @@ from mudlib.player import Player, players
 from mudlib.store import account_exists, load_player_data, set_admin
 from mudlib.things import spawn_thing, thing_templates
 from mudlib.zone import Zone
-from mudlib.zones import get_zone, register_zone
+from mudlib.zones import get_zone, register_zone, zone_registry
 
 # Content directory, set during server startup
 _content_dir: Path | None = None
@@ -180,6 +180,24 @@ async def cmd_demote(player: Player, args: str) -> None:
     await player.send(f"{target_name} is no longer an admin.\r\n")
 
 
+async def cmd_zones(player: Player, args: str) -> None:
+    """List all registered zones."""
+    if not zone_registry:
+        await player.send("No zones registered.\r\n")
+        return
+
+    await player.send("zones:\r\n")
+    current_zone_name = (
+        player.location.name if isinstance(player.location, Zone) else None
+    )
+
+    for name in sorted(zone_registry.keys()):
+        zone = zone_registry[name]
+        dimensions = f"{zone.width}x{zone.height}"
+        marker = "  [here]" if name == current_zone_name else ""
+        await player.send(f"  {name:<15} {dimensions:>6}{marker}\r\n")
+
+
 register(CommandDefinition("@goto", cmd_goto, admin=True, help="Teleport to a zone"))
 register(CommandDefinition("@dig", cmd_dig, admin=True, help="Create a new zone"))
 register(CommandDefinition("@save", cmd_save, admin=True, help="Save current zone"))
@@ -190,3 +208,4 @@ register(
 register(
     CommandDefinition("@demote", cmd_demote, admin=True, help="Revoke admin status")
 )
+register(CommandDefinition("@zones", cmd_zones, admin=True, help="List all zones"))
diff --git a/tests/test_build_commands.py b/tests/test_build_commands.py
index 91b751c..b25bfde 100644
--- a/tests/test_build_commands.py
+++ b/tests/test_build_commands.py
@@ -325,3 +325,132 @@ async def test_builder_commands_require_admin(zone, mock_writer, mock_reader):
     mock_writer.write.assert_called()
     written = mock_writer.write.call_args_list[-1][0][0]
     assert "permission" in written.lower()
+
+
+# --- @zones ---
+
+
+@pytest.mark.asyncio
+async def test_zones_lists_registered_zones(player):
+    """@zones lists all registered zones."""
+    from mudlib.commands.build import cmd_zones
+
+    # Register additional zones
+    forest = Zone(
+        name="forest",
+        width=15,
+        height=12,
+        terrain=[["." for _ in range(15)] for _ in range(12)],
+    )
+    register_zone("forest", forest)
+
+    tavern = Zone(
+        name="tavern",
+        width=8,
+        height=6,
+        terrain=[["." for _ in range(8)] for _ in range(6)],
+    )
+    register_zone("tavern", tavern)
+
+    await cmd_zones(player, "")
+
+    # Check all zones are listed
+    all_output = "".join(call[0][0] for call in player.writer.write.call_args_list)
+    assert "hub" in all_output
+    assert "forest" in all_output
+    assert "tavern" in all_output
+
+
+@pytest.mark.asyncio
+async def test_zones_shows_dimensions(player):
+    """@zones shows width x height for each zone."""
+    from mudlib.commands.build import cmd_zones
+
+    forest = Zone(
+        name="forest",
+        width=20,
+        height=15,
+        terrain=[["." for _ in range(20)] for _ in range(15)],
+    )
+    register_zone("forest", forest)
+
+    await cmd_zones(player, "")
+
+    all_output = "".join(call[0][0] for call in player.writer.write.call_args_list)
+    assert "10x10" in all_output  # hub from fixture
+    assert "20x15" in all_output  # forest
+
+
+@pytest.mark.asyncio
+async def test_zones_highlights_current_zone(player):
+    """@zones marks the player's current zone."""
+    from mudlib.commands.build import cmd_zones
+
+    forest = Zone(
+        name="forest",
+        width=15,
+        height=12,
+        terrain=[["." for _ in range(15)] for _ in range(12)],
+    )
+    register_zone("forest", forest)
+
+    await cmd_zones(player, "")
+
+    all_output = "".join(call[0][0] for call in player.writer.write.call_args_list)
+    # hub should be marked as current (player is in hub via fixture)
+    assert "[here]" in all_output
+    # [here] should be on the same line as hub
+    hub_line_idx = all_output.find("hub")
+    here_idx = all_output.find("[here]")
+    assert hub_line_idx < here_idx < hub_line_idx + 50
+
+
+@pytest.mark.asyncio
+async def test_zones_empty_registry(zone, mock_writer, mock_reader):
+    """@zones with no zones shows appropriate message."""
+    from mudlib.commands.build import cmd_zones
+
+    # Create player not in a zone fixture
+    zone_registry.clear()
+    temp_zone = Zone(
+        name="temp",
+        width=5,
+        height=5,
+        terrain=[["." for _ in range(5)] for _ in range(5)],
+    )
+    p = Player(
+        name="builder",
+        x=0,
+        y=0,
+        writer=mock_writer,
+        reader=mock_reader,
+        location=temp_zone,
+        is_admin=True,
+    )
+
+    await cmd_zones(p, "")
+
+    mock_writer.write.assert_called()
+    written = mock_writer.write.call_args_list[0][0][0]
+    assert "no zones" in written.lower()
+
+
+@pytest.mark.asyncio
+async def test_zones_requires_admin(zone, mock_writer, mock_reader):
+    """Non-admin players cannot use @zones."""
+    from mudlib.commands import dispatch
+
+    non_admin = Player(
+        name="player",
+        x=5,
+        y=5,
+        writer=mock_writer,
+        reader=mock_reader,
+        location=zone,
+        is_admin=False,
+    )
+
+    await dispatch(non_admin, "@zones")
+    mock_writer.write.assert_called()
+    written = mock_writer.write.call_args_list[-1][0][0]
+    assert "permission" in written.lower()