Improved Survival Mode
Requires the City Economic Simulation DLC · Survival Mode. Town isolation is a setting on the Survival Mode page, which itself is part of the City Economic Simulation DLC. Turn Survival Mode on when you start a new game and the isolation options appear beneath it. If you play Survival Mode without this feature (or turn it off), the game behaves exactly as it did before.
A game in two phases
The feature gives the early game a clear shape. Instead of being contested from day one, a Survival Mode game now runs in two acts:
| Phase | What it means |
|---|---|
| Phase 1 · Isolation: Your town is yours | For the length of the isolation period you are the only company that can build in your town, and the AI grows its own separate town. Use the breathing room to establish supply chains, build cash, and secure the best land — without a rival undercutting you on day one. |
| Phase 2 · Open market: The borders come down | Once the period ends, every company — you and the AI — can build in any town. Your competitors, who have been developing their own town all along, can now move into yours, and you can finally expand into theirs. |
Play toward the deadline. The end of the isolation period is a moment you can prepare for. The companies growing in the AI town will arrive as real competitors — so spend Phase 1 getting strong enough to meet them, not just comfortable. When the market opens, you want to be the one expanding outward, not the one being moved in on.
Turning it on and setting the length
Both controls live on the Survival Mode page when you set up a new City Economic Simulation game:
- Start a new game and enable the City Economic Simulation DLC.
- On its settings, set Survival Mode to Yes. The survival options appear below it.
- Set Town Isolation at the Beginning to Yes (it is on by default). A second control appears to its right.
- Use the Isolation Period (Years) slider to choose how many years the isolation lasts.
| Setting | What it does | Default |
|---|---|---|
| Town Isolation at the Beginning | Master on/off switch. When No, Survival Mode plays as it always did: a single town and no building restrictions. | Yes |
| Isolation Period (Years) | How long the two towns stay closed to each other. Shown only when isolation is on. | 10 years |
To switch the feature off entirely, set Town Isolation at the Beginning to No — the years slider disappears and you get the classic single-town Survival Mode start. There is no need to drag the slider to zero.
What you can and can’t build during isolation
While the isolation period is running, the rule is simple: each side builds only in its own town.
| Who | Your town | The AI town |
|---|---|---|
| You (your company) | Build freely | Blocked until the period ends |
| AI companies | Cannot build here | Build freely |
If you try to place a building in a town that isn’t yours during the isolation period, the placement marker turns red and a message explains why, telling you how many years remain until the towns open:
“During the Survival Mode isolation period, you can only build in your own town. The other towns open up in N year(s).”
Your work as mayor is never blocked. The isolation rule applies only to companies. Public and government buildings you construct as the town’s mayor are exempt, so running and developing your city is completely unaffected — only company expansion into the other side’s town is held back.
When the isolation period ends
The moment enough years have passed, the restriction simply lifts — there is nothing you need to do. From that point on:
- You can build in any town, including the AI’s.
- AI companies can build in any town, including yours.
- Everything you and the AI built during Phase 1 stays exactly where it is — only new construction was ever restricted.
The next time you open the build menu in a town that was previously off-limits, you’ll find you can place buildings there normally. That is your signal that the open-market phase has begun.
What your competitors are doing
The AI companies are not idle during isolation — they are busy building up their own town under exactly the same rule that keeps them out of yours. By the time the period ends, they are established businesses with their own factories, retail and cash. When the borders come down they will look to expand, and your town is now fair game. Treat the end of isolation as the start of real competition, not a formality.
Using the isolation period well
- Bank the calm. With no rival in your town, prices and demand are yours to shape. Build the vertically-integrated supply chain and the cash reserve you’ll want when competition arrives.
- Claim the ground. Secure prime downtown and resource locations in your own town early — they’ll be far harder to grab once the market opens and buyers multiply.
- Set the length to your taste. A short period (a few years) keeps the pressure on; a long one lets you build a commanding lead first. A game often runs for decades, so a very long isolation is a large slice of it — pick the balance you enjoy.
- Don’t just get comfortable — get strong. A monopoly that never had to compete can be a fragile one. Use Phase 1 to become genuinely efficient, so you’re ready for the companies coming out of the AI town.
- Prefer it for a gentler start. If Survival Mode’s usual day-one pressure has felt overwhelming, isolation is the setting that gives you a foothold first. If you want the classic gauntlet, turn it off.
At a glance
| Question | Answer |
|---|---|
| What do I need? | City Economic Simulation DLC, with Survival Mode on |
| Where do I set it? | New game → Survival Mode page → Town Isolation at the Beginning + Isolation Period (Years) |
| Is it on by default? | Yes — with a 10-year period. Set the toggle to No to disable it. |
| What happens during isolation? | You build only in your town; the AI builds only in its own town |
| Does it restrict my mayor / public building? | No — only company expansion into the other side’s town is blocked |
| What happens when it ends? | Every company can build in every town; existing buildings are untouched |
See also: Version 12.5 new features.