Invasion active now!
Next invasion in:
Faction Assaults (formerly named Incursions) start with WoW Patch 8.1. They work in a similar way to Legion Invasions, however the enemy is now the opposing faction. Horde and Alliance have Faction Assaults in the same zone, one as the attacker, one as the defender - Horde and Alliance have mostly shared quest areas, Warmode can be dangerous!
Faction Assaults last for 7 hours (up from the 6 hour duration of Legion Invasions). The next Faction Assault will then begin 12 hours after the last one finished. This means that there will be one Faction Assault every 19 hours.
You must be at least level 110 to take part in the Faction Assault. Level 110 characters who have not yet been to the opposite continent must gain 100 war resources and turn it in as part of the war campaign to sail over.
You can also find a friendly warlock to summon you over. Be sure to pick up the flight path map from the 7th Legion or Honorbound vendor if you have a character with BFA Pathfinder Part 1.
While levelling between levels 110 - 119, Faction Assaults have between 4 and 7 World Quests available to complete, the average being 5. Rewards from these World Quests include bonus experience (most common), war resources, and azerite.
You must complete at least 4 world quests to do the final quest, which unlike Legion Invasions, is available to all characters including levelling characters. Completing this final quest will award 5 Service Medals, along with 1000 reputation with The Honorbound or 7th Legion if on the enemy's continent, or 500 reputation and 500 of the zone's reputation if you are fighting on your own continent. Levelling characters will also receive some experience and a 10% experience bonus that lasts for one hour and persists through death.
Level 120 characters will find the same quests with different rewards. Reputation, gold, azerite, experience, and gear are available as rewards. You can also earn Conquest (PvP currency) if you have War Mode enabled.
With no heirlooms active, don't expect to be gaining a level each time you do a Faction Assault - these award far less exp than Legion Invasions. But it should still be one of the fastest levelling methods 111-120. The biggest gain to levelling from these will be the 10% experience bonus buff you gain from completing the final quest.