From Guild Wars 2 Wiki
Weapon swap is the mechanic of switching between the two equipped weapon sets (default key: ). This ability is unlocked when your character reaches level 15 for all professions except engineers or elementalists, who use a similar mechanic.
- During combat, swapping has a cooldown of 10 seconds, but you can swap repeatedly out of combat.
- There are several traits and sigils effects that trigger on swapping.
- If you choose to leave either the main hand or offhand weapon slot empty in one of the sets, the game will not swap the empty slot, and instead automatically use the weapon in that slot from the first set when you switch to the second.
- Engineers can trigger on-swap effects by changing kits; elementalists do so by switching between attunements.
- Switching to an environmental weapon will also trigger on-swap effects.
- Versatile Rage (gain 5 strikes of adrenaline)
- Fast Hands (cooldown reduced by 5 seconds)
- Versatile Power (gain might for 10 seconds)
- Tail Wind (gain swiftness)
- Furious Grip (gain fury)
- Quick Pockets (gain 3 initiative)
- Superior Rune of the Warrior (rank 6 – weapon-swap cooldown reduced by 20%)
- Sigil of Battle (gain [2, 3] stacks of might for 20 seconds)
- Superior Sigil of Doom (next attack poisons)
- Superior Sigil of Energy (gain 50% endurance)
- Superior Sigil of Geomancy (bleeds nearby foes for 7 seconds)
- Superior Sigil of Hydromancy (freeze nearby foes for 3 seconds)
- Superior Sigil of Intelligence (next attack has a 100% critical hit chance)
- Superior Sigil of Leeching (next attack steals health)
- Rearranging or equipping a different set of weapons is not the same as swapping. This can be done outside of combat, but never during combat. It never triggers on-swap effects.