FSX works offline in single-player. Learn how Steam Edition multiplayer, boxed FSX LAN/direct connections and obsolete GameSpy support differ.
FSX can be played entirely offline in single-player. Multiplayer requires a network connection: FSX: Steam Edition uses Steam for online sessions, while boxed FSX's old GameSpy browser no longer works. Boxed editions can still use a local network or compatible direct connection, but Steam and boxed multiplayer are not normally interoperable.
What works online and offline in each FSX version?
The available multiplayer method depends on whether you have FSX: Steam Edition or the original boxed release.
| Mode | FSX edition | Internet needed? | What to expect |
|---|---|---|---|
| Single-player | Both | No, once installed and activated | Free Flight, missions, lessons, AI traffic, built-in ATC and weather themes work offline. |
| Steam multiplayer | Steam Edition | Yes | Steam must be online. Players host or join sessions through Steam networking. |
| GameSpy multiplayer | Boxed FSX | Unavailable | The original public GameSpy browser is obsolete and cannot be used to find sessions. |
| LAN multiplayer | Boxed FSX | No internet, but a local network is required | Suitable for computers connected to the same router or local network. |
| Direct connection | Boxed FSX | Only when players are in different locations | Remote hosting may require firewall permission and router configuration. |
If you are unsure which release you own, our breakdown of Steam Edition versus boxed FSX explains their networking and installation differences.
How do you play FSX multiplayer?
Use Steam networking with FSX: Steam Edition, or LAN/direct connection options with a boxed copy.
- Identify your edition. Steam Edition displays and launches through Steam. A boxed installation does not gain Steam multiplayer merely because it has been added to the Steam library as a shortcut.
- Choose the connection method. Put Steam online before opening Steam Edition multiplayer. With boxed FSX, select a local-network session or connect directly to a known host rather than trying the retired GameSpy browser.
- Use a separate installation for each player. FSX has no split-screen or same-PC multiplayer. Every participant needs a computer running a licensed installation.
- Match the simulator versions. Boxed players should use the same service-pack or Acceleration update level. Steam and boxed installations should not be expected to see or join each other's built-in sessions.
- Allow FSX through the firewall. The host and clients must permit the simulator's network traffic. A remote boxed host may also need appropriate router forwarding.
- Test with default aircraft. Add-on aircraft can introduce mismatched models, missing animations or shared-cockpit problems. Establish a working connection first, then add the intended aircraft.
Can FSX multiplayer work without internet?
Boxed FSX can run multiplayer over a LAN without internet access, but the computers must still be connected to the same local network.
FSX: Steam Edition's built-in multiplayer depends on Steam being online, so Steam Offline Mode is suitable for single-player rather than multiplayer. LAN play also requires one computer per participant; there is no couch co-op mode.
Shared cockpit is a multiplayer feature rather than an offline two-player mode. Both participants need compatible simulator versions and, where required, the same aircraft installation.
Why can't I find or join an FSX session?
Most FSX multiplayer failures come from using the wrong networking method, mixing editions or blocking the host connection.
- GameSpy shows no sessions: this is expected on boxed FSX because the service was discontinued. Use LAN or direct connection instead.
- Steam sessions are missing: confirm that Steam is online, both players are using Steam Edition and the session is not private, full or hidden by filters.
- The connection times out: check Windows Firewall and any security software on both computers. For remote direct connections, the host's router or carrier-grade NAT may block incoming traffic; another participant may need to host.
- Players connect but aircraft look wrong: missing add-on models are often replaced by a default aircraft. Install matching aircraft and liveries when visual consistency matters.
- Shared cockpit behaves incorrectly: test with a default aircraft and matching update levels. Complex add-ons may not synchronise every switch or system.
Is VATSIM the same as FSX multiplayer?
No. VATSIM is an online pilot-and-controller network accessed through a compatible pilot client, not the session browser built into FSX.
Choose ordinary FSX multiplayer for private flying, formation practice or shared cockpit. Choose VATSIM when you want structured online ATC and traffic operating under network procedures; our FSX VATSIM connection guide covers the separate client setup.