Where to find and catch Thundurus in Pokémon Legends: Arceus

gamepur.com:

There are several legendary Pokémon for you to catch in Pokémon Legends: Arceus. Many Pokémon are tied to specific quests that unlock as you progress through the story. After you’ve completed the Giratina quest and captured it to add to your Pokédex, your next stop is to learn about the Forces of Nature legendary Pokémon. Thundurus is one of these Pokémon, and you’ll have to seek it out in the Cobalt Coastlands. In this guide, we cover where to find and catch Thundurus in Pokémon Legends: Arceus.

You can only begin looking for Thundurus after you have completed the On the Trail of Giratina request, which you receive after completing the mission Seeking the Remaining Plates. After that, Thundurus will be one of the three Pokémon you’ll have to catch for the Incarnate Forces of Hisui request.

Thundurus will spawn in the Cobalt Coastlands. You’ll need to wait for it to be heavily raining before this happen. If it’s not raining hard when you reach the Coastlands, go to a tent at base camp and rest on any of the days, and force the weather to reset. You’ll have to do this until you get stormy weather.

Once you have stormy weather, you’ll find Thundurus wandering around in the water north of Sand’s Reach. It will run away when you attempt to get close to Thundurus, throwing tornados at you. You’ll need to use Basculegion to bypass these tornados, throw your Pokémon at it to stun it, and then throw it again to start a battle. Stunning Thundurus will be the tricky part.

After catching Thundurus, you’ll need to find the other two Forces of Nature in Hisui to complete the rest of the request.