* Finding a Tirtouga Fossil: This is the most common way to get a Tirtouga. The fossil is found in certain locations in various Pokémon games, and it can then be revived to become a Tirtouga.
* Trading with another player: You can trade with someone who has already obtained a Tirtouga.
It's important to remember that Tirtouga is not available in every Pokémon game. You'll need to check the specific game you're playing to see if it's possible to obtain a Tirtouga in that game.