A full game of Messina lasts ten Rounds. Each Round consists of:
- An Action Phase
- A Military Operations Phase
- Missiles (includes Demolition Attacks)
- Marches (includes provision of Support if battles occur)
- Manoeuvres (including Moves, Convoys and Bombing Raids)
- An Alternating Phase (Mustering or Consumption)
- A Maintenance Phase
Actions are chosen in order, starting with the player holding the First Player Marker, and proceeding clockwise (odd-numbered Rounds) or anticlockwise (even-numbered Rounds). The First Player Marker has a clockwise side and an anticlockwise side. It starts in front of the AI player with its clockwise side face-up; it must be flipped and passed to the left at the end of each Round. The First Player for each Round therefore proceeds in a clockwise order, even though play direction alternates. In a standard game, every player gets two Rounds in which they are the First Player.
|Round 1: AI, UE, SF, FF, Cr||Round 6: AI, Cr, FF, SF, UE|
|Round 2: UE, AI, Cr, FF, SF||Round 7: UE, SF, FF, Cr, AI|
|Round 3: SF, FF, CR, AI, UE||Round 8: SF, UE, AI, Cr, FF|
|Round 4: FF, SF, UE, AI, Cr||Round 9: FF, Cr, AI, UE, SF|
|Round 5: Cr, AI, UE, SF, FF||Round 10: Cr, FF, SF, UE, AI|
|Odd Rounds||Even Rounds|
During every Action Phase, each faction in turn must choose one of the 6 Actions by placing a cone-shaped Action Pawn on a vacant Action Space that has not yet been used for the Round. During online playtesting, this form can be used to choose an Action and provide details about its execution.
A Military Operations Phase occurs if any faction has chosen the Militarisation Action.
The Alternating Phase of odd-numbered Rounds is a Muster, during which factions spend Energy to build new Military Units or Shields. The Alternating Phase of even-numbered Rounds is a Consumption Phase, during which players spend Food and Water to maintain their Population.
Every Round except the final Round ends with a brief Maintenance Phase.
The Alternating Phase for the final Round of the game is the Final Consumption Phase, during which pairs of factions contending for victory pool all Commodities and Utilities and see how many Population Tokens can be adequately supported.