Combat in MS Saga is subject to a number of rules and guidelines.
- Explosives (missiles, rockets, bazookas etc.) are weak against machine gun and other rapid firing weapons such as Head-Mounted Vulcans and Vulcan Cannons.
- Solid weapons are more effective against non-physical shields like I-Fields than beam weapons.
- All non-aquatic beam weapons have their output halved under water, any beam sabres or blades, which the exception of the Beam Pick, are disabled under water.
- If a weapon requires turns to switch modes, the weapon can not be used the turn you switch it on. If the weapon requires a charge time, you can not use it on the turn it finishes it's charging on.
- "Rounds per fire"/"Cost per shot" refers to the number of objects fired per turn. Note: certain double weapons may have a single charge but fire from two barrels per turn, in this case it will be annotated with "(Double Shot)".
- "Ammunition Level"/"Rounds per clip"/"Charge Level"/"Rounds per charge" refers to a weapon's total ammunition storage size.
- A sandy arena or a thick layer of snow can hinder the movements of a mobile suit that is not properly equipped. The speed of a mobile suit is cut in half in such an environment.
- Complete submersion in water can hinder the movements of a a mobile suit that is not properly equipped. The speed of a mobile suit is cut in half in such an environment.
- A mobile suit that is not properly equipped for space can not move in zero gravity at all.
- Stealth levels and Heat levels effect each other.
- A heat level of 0-50 can not be seen with heat sensors.
- 51-99 can be seen slightly, though not easily.
- 100-150 can be seen only with heat sensors.
- 151+ can be seen by anyone without a heat sensors.
- The stealth level removes that amount of heat from the infra-red spectrum.
- When battle begins, the first round will determine the battle order. Unless a new unit enters the battle field, this will be set for the entire battle. The spot where the new unit enters will be it's turn in the battle.