Two of the same civilization's team bonuses do not stack, but a team bonus can stack with another bonus. It is also important to note that should a player be defeated or resigns, their team bonus remains active for their allies. However, In diplomacy games (with no locked teams), team bonuses do not affect allies. This is because team bonuses function as a technology that is researched at the beginning of the game, and as such, changing allies mid-game will not transfer the team bonus. A team bonus can be applied in a diplomacy game if players set their team at the beginning of the game.
The following list shows of team bonuses.
- Aztecs: Relics generate 33% more gold.
- Berbers: Genitours are available at the Archery Range in the Castle Age.
- Britons: Archery Ranges work 20% faster.
- Bulgarians: Blacksmiths work 50% faster.
- Burmese: Relics are visible on the map from the game start.
- Byzantines: Monks heal 50% faster.
- Celts: Siege Workshops work 20% faster.
- Chinese: Farms provide +45 food.
- Cumans: Palisade Walls have +50% hit points (HP).
- Ethiopians: Towers and Outposts have +3 Line of Sight (LOS).
- Franks: Knight line has +2 LOS.
- Goths: Barracks work 20% faster.
- Huns: Stables work 20% faster.
- Incas: Farms are built 100% faster.
- Indians: Camel Rider line has +6 attack against buildings. Ranged Camel units have +5 attack against buildings.
- Italians: Condottieri are available at the Barracks in the Imperial Age.
- Japanese: Galleys have +50% LOS.
- Khmer: Scorpions have +1 range.
- Koreans: Mangonel line minimum range reduced to 1 in the Definitive Edition, reduced by 1 in The Forgotten. Mangonel line maximum range increased by 1in The Conquerors.
- Lithuanians: Monasteries work 20% faster.
- Magyars: All foot archers (excluding elite and non-elite Skirmishers; including Imperial Skirmishers) have +2 LOS.
- Malay: Docks and Harbors have +100% LOS.
- Malians: University researches 80% faster.
- Mayans: Walls and Gates are 50% cheaper (Stone Walls -2 stone per segment, Palisade Walls -1 wood).
- Mongols: Scout Cavalry line has +2 LOS.
- Persians: Knight line has +2 attack against archers.
- Portuguese: Free Cartography from the Dark Age.
- Saracens: All foot archers have +2 attack against standard buildings.
- Slavs: Military production buildings (except Castles and Kreposts) provide +5 population.
- Spanish: Trade Carts and Trade Cogs return 25% more gold.
- Tatars: All Cavalry Archers have + 2 LOS.
- Teutons: All units resist conversion.
- Turks: Gunpowder units are created 25% faster.
- Vietnamese: Elite Skirmishers can be upgraded to Imperial Skirmishers in the Imperial Age.
- Vikings: Docks are 15% cheaper.
Note that while not technically a team bonus, the Berbers' Castle Age unique technology Kasbah can be considered a team bonus as well since it, like regular team bonuses, affects the entire team. Unlike normal team bonuses, the effects of Kasbah stack if multiple Berber teammates research it. The Vietnamese and Cumans also have unique Imperial Age technologies that benefit the entire team: Paper Money and Cuman Mercenaries. But since they are both one-time use, it is arguable whether they can be considered team bonuses.
Out of all 40 unique units in the game, three are available as team bonuses: the Condottiero, Genitour, and Imperial Skirmisher. These are often used to supplement lacking unit lines (for example Condottieri can make up for the Persians' lacking Militia line, and Aztec Imperial Skirmishers surpass the Aztec Arbalester), or to cover a niche, such as a late Imperial Age trash game.