Ups resistance to Fire and Ice.
Thick Fat is an ability that reduces the damage taken from Fire-type and Ice-type moves by 50%. This means that if a Pokémon with Thick Fat is hit by a Fire or Ice move, the damage it takes will be halved, making it more resilient against these types of attacks. Thick Fat is particularly useful for Pokémon that are weak to Fire or Ice moves, as it helps them survive longer in battles.
| Azumarill | Primary | Unknown | |
| Azurill | Primary | Unknown | |
| Dewgong | Primary | Unknown | |
| Mamoswine | Hidden | Unknown | |
| Marill | Primary | Unknown | |
| Miltank | Primary | Unknown | |
| Munchlax | Secondary | Unknown | |
| Piloswine | Hidden | Unknown | |
| Raticate(alolan) | Hidden | Unknown | |
| Rattata(alolan) | Hidden | Unknown | |
| Seel | Primary | Unknown | |
| Snorlax | Secondary | Unknown | |
| Swinub | Hidden | Unknown | |
| Venusaur | Hidden | Unknown |