Armored Mewtwo is coming back to Pokémon GO for a limited run during the game’s Mega Finale event on September 5 and 6. The return gives players another chance to meet one of the game’s most recognizable raid bosses, but the window is short and the event has a firm local schedule.

Niantic says the Mega Finale will run from 10 a.m. to 6 p.m. local time on both days. Armored Mewtwo will appear in five-star raids. That means players will need a raid group and a stock of passes if they want to make several attempts during the weekend. The official event announcement does not say that the Pokémon will remain after the finale, so players should treat the two-day schedule as the main opportunity.

There is one important limit. Shiny Armored Mewtwo will not be available in this return. Players can still collect the regular version, add another entry to their battle roster or use the event to search for better stats. The lack of a shiny form also sets a clear expectation for collectors before they spend time or money on extra raids.

The comeback was announced at the 2026 Pokémon World Championships in San Francisco. The timing connects the in-game event with one of the franchise’s biggest competitive gatherings. It also gives the raid a stronger place in the September calendar, when many players are already planning around Pokémon GO Fest events and community activities.

Players should check the event page for local start and end times before heading out. Raid availability can vary by location, and busy gyms may fill quickly during the first hours. A group plan, remote-pass limits and counters that can handle a five-star battle will matter more than simply arriving at the gym.

Armored Mewtwo’s return is therefore a focused raid weekend, not a permanent addition or a confirmed shiny release. The official details point to a short event with one featured target. That makes the September 5–6 window the key date for trainers who missed its earlier appearances.