The game board is comprised of forty provinces, each with its own card. At the start of play, you receive a number of Province cards at random, then mark your initial positions with town pieces. Shuffle these Province cards with a set of five Initial cards to form your starting deck, then draw a hand of five cards. The game includes 27 Improvement cards, 16 of which are drawn and placed on display; these cards will be drafted during the game.
Mythotopia has nine variable victory point (VP) cards, four of which are drawn at random for a game; place these cards on display with three fixed VP cards, then place a number of VP counters on each card. The fixed VP cards give points for building cities, roads and castles, while the variable ones may change the board situation by adding dragons, runestones and citadels. Alternatively they may grant VPs for controlling a certain number of sea areas, for successfully attacking other players, and for building cities/roads. As these VP cards vary from game to game, they alter the balance between developmental and aggressive play.
On your turn, perform two actions, then refill your hand to five cards. Nine actions are possible, such as buying armies or ships (after starting with six armies and two ships), placing these armies or ships, drafting Improvement cards (for a cost of one gold), placing cards in reserve (to use them on a future turn), permanently removing cards from your deck, using a card for its specific action, and invading a neighboring province. To invade, you must play the Province card from which you attack as well as military cards and food; invading must be the first of your two actions, so if you're placing armies to prepare for an attack, opponents have the chance to prepare defenses.
Three resources are used in Mythotopia: food to feed invading armies, stone to build cities, roads and castles, and gold to buy armies, ships and Improvement cards. Most provinces contain one resource type, and gaining that province gives you that resource. You can turn towns into cities, which increases the number of cards you can keep in your reserve. You can connect provinces with roads, which allows you to substitute one card for another on the same network in addition to moving armies freely between those provinces. Castles increase the defensive value of a province.
All of these constructions (cities, roads, castles) give you victory points, as does taking control of a province. Additional points are available via the VP cards, with you taking VP counters when you meet the condition on a card. For example, building a road gives you two VPs, but if the "Roadside Inns" VP card is in play, then you can expend an extra gold to gain an additional VP. You can lose VPs if you lose control of a province, but you never lose VP counters. The game ends after four of the seven VP cards have been emptied, and the player with the most VPs wins.
Your turn is divided into two phases. In the first phase, you choose to either conduct commerce (such as selling goods, taxing locations or improving your warehouse) or take a card, selecting one from seven on display; the cards vary in their effects, granting money, victory points or special actions.
In the second phase, you choose whether to place a ship, move a ship, or retrieve ships/merchants. When you place a ship, you do so in either the merchant box or the warship box in one of eleven levels. A merchant allows you to place a merchant cube on the board, giving you one or two goods counters to place in your warehouse. A warship lets you take control of a location at the cost of one food goods counter.
Once all of your ships are on the board, you can either move them (paying money to advance its level and take the associated action) or retrieve it from the board so that you can place it elsewhere later. As ships are placed in a level, the cost of placing in the next level reduces — until finally somebody is willing to pay the cost to place in that level (which earns bonus points and possible additional income). When a ship is placed in the first galleon level, galleys become redundant; similarly, someone placing in the first steamship level makes galleons redundant. During the galleon and steamship ages, you can pay extra to move more ships, so having money in hand gives you a greater range of options and allows you to use your fleet more efficiently.
When placing ships, you can initially place only in "1" locations, which are grouped around the eastern Mediterranean Sea. Once someone pays to move to a "2" location, which are grouped around the western Mediterranean, that area opens to others, with the other areas being Northern Europe (3), the Americas (4), East Indies (5) and the Pacific (6). As soon as a new area opens, players score points for merchants and control discs in the present area, with the points earned being the same as the number of the area.
Ships includes six types of goods: food, oil, metal, wine, cloth and spices. Each has a monetary value as well as a special power. Food can be used to take control of locations, thus building an empire. Oil can be used to gain extra actions. Metal helps to advance your ships along the outer track. Wine can be converted to goods of a lower value. Cloth can be converted to victory points, while spices have the highest monetary value. You have to decide whether to cash your goods in for money or use their power.