Main Series Games:
* Pokémon Gold and Silver: Entei is a Legendary Pokemon that can be encountered and caught in these games.
* Pokémon Crystal: Entei is a Legendary Pokemon that can be encountered and caught in this game.
* Pokémon HeartGold and SoulSilver: Entei can be encountered and caught in these remakes of Gold and Silver.
* Pokémon Black and White: Entei can be encountered and caught in these games after completing the post-game.
* Pokémon Black 2 and White 2: Entei is a Legendary Pokemon that can be encountered and caught in these games.
* Pokémon X and Y: Entei is a Legendary Pokemon that can be encountered and caught in these games through the Friend Safari.
* Pokémon Omega Ruby and Alpha Sapphire: Entei can be encountered and caught in these remakes of Ruby and Sapphire through the Delta Episode.
* Pokémon Sun and Moon: Entei is a Legendary Pokemon that can be encountered and caught in these games through the Island Scan feature.
* Pokémon Ultra Sun and Ultra Moon: Entei is a Legendary Pokemon that can be encountered and caught in these games through the Island Scan feature.
* Pokémon Let's Go, Pikachu! and Let's Go, Eevee!: Entei can be encountered and caught in these games through the post-game, as part of the "Catching the Legendary Beasts" event.
* Pokémon Sword and Shield: Entei is a Legendary Pokemon that can be encountered and caught in this game through the Max Raid Battles.
* Pokémon Brilliant Diamond and Shining Pearl: Entei can be encountered and caught in these remakes of Diamond and Pearl by completing the post-game.
* Pokémon Legends: Arceus: Entei is a Legendary Pokemon that can be encountered and caught in this game after completing the main story.
* Pokémon Scarlet and Violet: Entei is a Legendary Pokemon that can be encountered and caught in this game through the Tera Raid Battles.
Other Games:
* Pokémon GO: Entei is a Legendary Pokemon that can be encountered and caught in this mobile game.
* Pokémon Masters EX: Entei is a playable character in this mobile game.
Note: The exact methods for encountering and catching Entei may vary depending on the specific game.