Multiplayer hub
Ace Combat Online Guide — Modes, Air Base & Progression
Ace Combat Online is Ace Combat 8’s multiplayer layer with separate save data from Campaign, full cross-play, a 100-player Air Base hub, core modes Co-Op Assault & Co-Op Warfare, plus random Scramble / Emergency Sortie specials and Ace Pass seasons.
Official Online Player intent
What is Ace Combat Online?
Developed by PROJECT ACES / Bandai Namco Aces. Bandai Namco bills Ace Combat Online as the largest multiplayer suite in the series. You enter as a mercenary pilot with a customizable avatar, hang out in the Air Base lobby, then sortie into score-driven co-op modes while earning Online-only progression and Ace Pass XP.
Campaign vs Online — critical difference
- Online uses its own progression and save data.
- Campaign Aircraft Tree unlocks do not auto-transfer; earn Online aircraft through Online rewards/shop paths.
- Some Deluxe/Pass cosmetics are Online-first.
Core modes at a glance
| Mode | Format | Goal |
|---|---|---|
| Co-Op Assault | Two teams of 4 (PvE score race) | Highest team score vs NPC enemies |
| Co-Op Warfare | 4v4 PvPvE | Highest score with NPC land/sea/air in the mix |
| Scramble | 4 players vs elite NPCs | Limited-time special while in core modes |
| Emergency Sortie | Up to 8 vs superweapons | Limited-time colossal boss fights |
Limited-time PvP events (4v4 team and 8-player deathmatch) are also planned in Online.
Aircraft roles & Online acquisition
Per Bandai’s Online FAQ, you can fly Fighters, Attackers, Multirole, and Electronic Warfare aircraft — the same roster types as Campaign. Ace Combat Online is still a standalone progression layer: aircraft must be earned again through mercenary rewards / Online shop paths (Campaign Tree unlocks do not carry over). Deep dive: Online aircraft acquisition.
Online error ST-3100001 (fix)
Official ACE COMBAT Team note: ST-3100001 means communication with the Ace Combat Online server was lost. The first check on PC is Windows time sync — even a 1–2 minute clock offset can break match session auth after Air Base / loadout screens.
- Settings → Time & language → Date & time → turn on Set time automatically and sync now.
- Optional check:
w32tm /stripchart /computer:time.windows.com /samples:5 /dataonly— offsets should be near 0s. - Restart Steam + Ace Combat 8, then retry a sortie (not just the Air Base lobby).
This is separate from PC crash Error 01. If time sync fails to help, note platform, exact code, and whether you fail at match load vs lobby.
How to start Online
- Finish enough campaign onboarding if the game gates Online behind story progress (check in-game prompts).
- Create/customize your mercenary avatar.
- Enter the Air Base lobby.
- Matchmake into Assault or Warfare; watch for Scramble/Emergency pop-ups.
- Spend rewards, raise merc rank, progress Ace Pass.
Rewards loop
Mission clear rank and winning-team bonuses feed Offline/Online currency, aircraft, cosmetics, and Ace Pass XP. Use shops in the base for purchases with earned currency.
Online & co-op searches
From this Online hub, jump to Co-op Assault, Warfare, Scramble, and Ace Pass when search intent is multiplayer rather than campaign MRP.
FAQ
Is Ace Combat Online separate from the campaign?
Yes — separate save and progression.
Does Ace Combat 8 have cross-play?
Yes — full cross-platform Online support.
What are the main Online modes?
Co-Op Assault and Co-Op Warfare, plus Scramble and Emergency Sortie specials.
Is the Online plane list the same as Campaign?
Yes — same roster categories (including Electronic Warfare). You still unlock them separately inside Online. See Online aircraft.
What is Threat Level / Ace in Online?
Warfare-only star streak. 3-Star Threat Level grants the title “Ace.” Full notes: Co-Op Warfare.
How many players in the Air Base?
Up to 100 players in the Air Base lobby hub. Details: Air Base.
What is Ace Combat 8 error ST-3100001?
Lost communication with Online servers. On PC, synchronize Windows time first, then restart Steam/game and retry match entry.
Further reading
Looking for Ace Combat 8 co-op?
Jump to the dedicated co-op modes hub for Assault vs Warfare at a glance.
Season 1 special missions
Scramble, Emergency Sortie, and PvP rotations: Online events guide.
Related guides
Air Base · Co-Op Assault · Co-Op Warfare · Ace Pass
Primary: Ace Combat Online. Also: multiplayer, cross-play, Air Base, mercenary pilot. Fan guide — Bandai Namco FAQ cited.