In contrast to the previous installments of Age of Empires Series, in Age of Empires III and both of its expansions The WarChiefs and The Asian Dynasties, the unit upgrades of every civilization usually do not change the original name of the unit, and most of the cases only add a title word. A new upgrade becomes available in every age.
The original installment is the only in which some unit's names were changed for the Second Upgrade.
The upgrade effect is always applied to the base units stats. Some of the units available in later ages have better base stats because they don't get the early upgrades, thus their later upgrades are more powerful in comparison.
Fortress Age Upgrade Edit
- European: Veteran
- Native American: Elite
- Asian: Disciplined
Industrial Age Upgrade Edit
The Industrial Age upgrade adds +30% to HP and Attack for the unit, at a cost of 600 Wood and 600 Coin for the European, Indian and Japanese civilizations. For the Chinese, it is 300 Wood and 300 Coin, and for Native American civilizations it is 400 Wood and 200 Coin.
- European: Guard
- Native American: Champion
- Asian: Honored
Royal Guard Upgrade Edit
These are the units available:
- Hussar (Life Guard) - British
- Musketeer (Redcoat) - British
- Ruyter (Carabineer) - Dutch
- Halberdier (Nassauers) - Dutch
- Cuirassier (Gendarme) - French
- Skirmisher (Voltigeur) - French
- Uhlan (Czapka) - German
- Skirmisher (Needle Gunner) - German
- Hussar (Gardener) - Ottoman
- Grenadier (Baractu) - Ottoman
- Dragoon (Jinete) - Potuguese
- Musketeer (Guerreiro) - Portuguese
- Cavalry Archer (Tartar) - Russian
- Grenadier (Pavlov) - Russian
- Lancer (Garrochista) - Spanish
- Pikeman (Tercio) - Spanish
- Rodelero (Espada) - Spanish
Imperial Age Upgrade Edit
The Imperial Age upgrade adds +50% to HP and Attack for the unit, at a cost of 1500 Wood and 1500 Coin for European, Indian and Japanese civilizations, and 750 Wood and 750 Coin for the Chinese. Artillery upgrades cost 1000 Wood and 1000 Coin for Asian civilizations.
- European: Imperial
- Native American: Legendary
- Asian: Exalted
Auto Upgrades Edit
Some units in Age of Empires III upgrade automatically when reaching a new age, instead of the upgrade having to be bought and researched. These are usually units who aren't trained in the normal way, including Spahis and Consulate units.