Age of Sparta is a strategy game that combines base building/management with battles through a campaign and worldwide PvP, much like the developer's earlier title World at Arms with very similar mechanics. The player builds and manages a city in ancient Greece as the Persian general Xerxes attacks Athens. The environment allows players to construct bases with roads, boosters that increase efficiency and different types of buildings. Some of these generate income or resources, while others are used to train units or research new technology. There is a population limit and additional houses need to be built to increase the limit. The starting location can also be expanded in different directions.
Troops can be taken into battle with fights where the screen is divided through a diagonal line as in World at Arms. Units are placed on the battlefield and have statistics such as a global level, health, strength and defenses. They can be auto-deployed, but there is a rock-paper-scissors system in place based on strengths and weaknesses (agile, magic, premium and tough) where a tactical approach is rewarded. Battles are automated once started, but the player can still interfere by slashing incoming projectiles, activating bonuses or removing hazards, and activating a charged unit. Units gain experience, but can also die during battles. In the PvP battles, which are generated based on another player's strength and do not require the other player to be present, a victory can be followed by a raid to steal resources. Battles can take place on different types of terrain such as land or sea.
The game is free-to-play with coins as the basic currency and advertisements. They are mostly generated through buildings and victories. Diamonds are the premium currency and used to acquire specific buildings or troops, resurrect defeated units or skip the waiting times. Faith is required to enter battles as an energy/stamina system. There is also a social currency and a league system with six tiers to compete worldwide in alliances.