Regirock was sealed away by people long ago. If this Pokémon's body is damaged in battle, it is said to seek out suitable rocks on its own to repair itself.
As a former 5th tier Raid Boss, Regirock's CP was 42,768. Its maximum capture CP in Bonus Challenge was 1,784 and 2,230 when encountered Pokémon was boosted by weather.
Regirock was available in Raid Battles from August 16th until September 20th, 2018.[1][2]
It was temporarily replaced by Ho-Oh from August 25th to August 27th.
Regirock was available again in A Colossal Discovery from November 1st to November 4th, 2019.[3]
It was accidentally made in Raids on October 22nd, 2019 for a short period of time.[4]
During March to April 2019, Regirock was the reward of the Research Breakthrough once seven stamps had been obtained with a 1,338 of maximal CP.
Shiny form of Regirock was released with the beginning of A Colossal Discovery on November 1st, 2019.
Regirock is considered by player community as a part of the "Regi" Pokémon family — Regirock, Regice, Registeel, and Regigigas (Sinnoh-region Pokémon), but none of them is related with each other by evolution.