Bubble Sub: how to play, tips and FAQ
Free simulation game · No download · Phone, tablet and computer
Written by Xavier Eric Francois Guiter, who designed and built this game. Updated .
Bubble Sub is a city builder at the bottom of the sea, in 3D, with two halves that feed each other. Underwater, you swim a diver around a round reef with 60 seconds of air, picking up the pearls that 24 oysters push out of their shells. In the city, those pearls pay for bubbles: a house costs 3, a submarine dock 20, and fourteen kinds unlock as your population grows.
You never build anything yourself. Three mermaids live in a grotto at the edge of the reef, and when you pick a plot one of them swims over and sings the bubble into shape. Houses then need furnishing, room by room, because comfort is what brings residents, and residents are what unlock the next buildings. The first dives are quick, the first hour mostly goes into houses and shops.
- Planning
- Resource management
- Spatial layout
At a glance
- Bubbles
- 14 kinds on 30 plots
- Air
- 60 s, up to 190 s
- Furniture
- 26 pieces, 5 premium
- Rooms
- 8 types, up to 6 per house
- Mermaids
- 3, a 4th for 150 gems
- Freex Coins
- 5 per quest, 10 per city level
How to play Bubble Sub
- Tap Dive. Swim with WASD or the arrow keys on a computer, or the yellow stick on a phone, and drag to look around. Pearls under a golden light beam fly to your treasury as soon as you are close.
- Watch the air gauge. It refills inside the Hub at the center of the city. If it runs out, the mermaids carry you back and you keep your pearls.
- Back in the city, tap a glowing + plot, pick a bubble you can afford, and a free mermaid comes to build it.
- Tap a finished house, then Enter house. Choose a room, buy furniture with shells, and move, turn or recolor each piece.
- Follow the quest at the top of the screen. Each one pays shells or pearls, and 5 gems.
Controls
| Action | Computer | Phone or tablet |
|---|---|---|
| Swim | WASD or arrow keys | Drag the yellow stick |
| Dash | Shift | DASH button |
| Look around while diving | Drag with the mouse | Drag anywhere else |
| Move the city camera | Drag to turn, wheel to zoom, right-drag to pan | Drag to turn, pinch to zoom, two fingers to pan |
| Open a plot or a bubble | Click it | Tap it |
| Sea map | Click the radar or Map | Tap the radar or Map |
| Close a panel, leave a house | Escape | Close or City button |
Diving
The suit holds 60 seconds of air, plus 20 for each of the 5 tank levels researched in the Laboratory, plus 30 with the Deluxe Coral Suit. Inside the Hub the gauge refills by 30 seconds every second. It turns yellow at half and red at a quarter. A dash burns 1.5 seconds and recharges in 1.6, and each of the 10 jellyfish on the outer reef takes 8 seconds and pushes you back.
The 24 oysters sit between 50 and 104 meters from the center, three of them close to the city for the first dive. A pearl regrows 40 to 75 seconds after you take it. The chest in the shipwreck gives 3 pearls and 3 gems, then needs two and a half minutes to fill again. If you follow the tutorial, the air never runs out during its first dive.
Building and upgrading
The 30 plots form three rings of 6, 10 and 14 around the Hub. You start with 6 open, get 2 more at each city level, and can clear one more at any time for 6 pearls, then 9, then 12. A bubble costs 3 to 20 pearls and takes 10 to 34 seconds once its mermaid arrives. You can finish it at once for 2 shells per second left, or 1 gem per 15 seconds.
Every bubble goes up to level 3. A shop earns 1.8 times its base income at level 2 and 2.8 times at level 3, and a house gets two more rooms at each level. Removing a bubble gives back half its pearls, and premium furniture inside goes to storage.
Research costs shells. The Laboratory sells bigger tanks, the Submarine Dock a stronger pearl magnet (0.8 m more reach per level, 5 levels) and faster flippers (12% more speed per level, 4 levels).
Comfort, residents and happiness
A house holds 1 resident, plus 1 per level, plus 1 for every 15 comfort. Each piece of furniture has its own comfort value, from 1 for a chair to 12 for a pool and 24 for the premium Rainbow Pool. A room with its key item adds 10, and a wall or floor color other than the default adds 1 each.
Happiness starts at 30. Average comfort adds up to 30, the number of different services up to 25, police stations 6 each (up to 12) and arcades 3 each (up to 6). It drops by 8 when more than 6 residents share too few shops. Shops pay every few seconds, scaled by happiness: half their income at 0, one and a half times at 100. Each school adds 10%, up to 30%.
Tips to score higher
- A room counts as finished when it holds its key item: a bed in a bedroom, a stove in a kitchen, a tub in a bathroom. Each finished room adds 10 comfort.
- Shift (or DASH) gives a burst of speed for 1.5 seconds of air. Use it to cross open sand, not near jellyfish, since a sting costs 8 seconds anyway.
- The Breeding Center makes pearls on its own every 40 seconds. Once you have 24 residents it is the best way to stop diving for every bubble.
- Build a few shops early. A crowded city with too few services loses 8 happiness, and happiness scales every shop's income.
Common mistakes
- Waiting for the red warning to swim back. Turn around when the gauge turns yellow: the outer oysters are 50 to 100 meters from the Hub.
- Building only houses. Shops pay for furniture, upgrades and research, and too few of them cost 8 happiness.
- Leaving a bedroom without a bed. A room without its key item misses 10 comfort, most of a resident.
- Spending every gem on rushes. The fourth mermaid, at 150 gems, lets four bubbles go up at once for the rest of the game.
Bubble Sub FAQ
Can I buy gems?+
No. Nothing is for sale in Bubble Sub on GAMEFREEX. Gems come from playing: 5 for each quest, 10 for each city level and 3 from the shipwreck chest. They pay for the fourth mermaid, the deluxe suit, premium furniture and rushed constructions.
Does the city keep earning when I close the game?+
Yes, for up to three hours. When you come back, the city pays half of what its shops would have earned in that time. The save lives in your browser on this device.
Is there a score or a leaderboard?+
No. Bubble Sub has no end and no score, so nothing is sent to the leaderboards. You earn 5 Freex Coins for each quest you complete and 10 for each new city level.
Why is the game slow on my phone?+
The reef is a full 3D scene with hundreds of creatures and plants. On older phones it can drop frames. Closing other tabs helps, and the city view is lighter than a dive.
