August 2023 is another very exciting month for Pokemon GO Raids, with the return of Primal Pokemon and the debut of Mega Rayquaza, alongside plenty more Legendary and Mega Raid bosses!
These are all of the Pokemon that will be Legendary, Mega, or Primal Raid bosses in August 2023 and what dates they will be in Raids:
August 2023 Pokemon GO Legendary, Mega & Primal Raid Bosses & Dates
| Date | Featured Pokemon | Shiny Available? |
| July 25 – August 4 | Regidrago | No |
| July 25 – August 4 | Mega Tyranitar | Yes |
| August 4-16 | Cresselia | Yes |
| August 4-16 | Mega Gyarados | Yes |
| August 16- 23 August 27 – September 1 | Xerneas | Yes  |
| August 16- 23 August 27 – September 1 | Yveltal (Knows Oblivion Wing)  | Yes |
| August 16- 23 August 27 – September 1 | Mega Salamence | Yes |
| August 23-26 August 26 (10 AM – 6 PM) August 27 (10 AM – 11 AM) | Primal Kyogre | Yes |
| August 23-26 During Pokemon GO Fest Global: August 26 (10 AM – 6 PM) August 27 (10 AM – 11 AM) | Primal Groudon | Yes |
| During Pokemon GO Fest Global: August 27 (11 AM – 6 PM) | Mega Rayquaza | Yes |
The fact that all of these Pokemon, apart from Regidrago, have shiny versions available in Pokemon GO is excellent news for shiny hunters. The odds of getting shiny Legendaries from Raids is 1 in 20, while the odds of encountering a shiny Pokemon after winning a Mega Raid is 1 in 64.
It is also worth noting that Mega Rayquaza will only be in Raids worldwide on Sunday, August 27, during the Pokemon GO Fest: Global event. However, it will also be available to battle during the in-person London, Osaka, and New York GO Fest events, earlier in the month.
