Tentacool evolves into Tentacruel starting at level 30.
Tentacool is #72 in the National Pokedex, and was introduced in the Generation I Pokemon titles (Red, Blue, and Yellow) where it could be found on Routes 17-21 and in Pallet Town (and other areas specific to each game). In Generation VI (X and Y), it is available on Routes 8 and 12, in Ambrette Town, Azure Bay, and in Cyllage and Shalour Cities.
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Tentacool evolves at Level 30. If you have caught a Tentacool that is somewhat over that level, it will evolve on the next 'level-up.'
Lv. 30
Tentacool evolves into Tentacruel at level 30.
Tentacool evolves into Tentacruel at level 30.
Tentacool evolves into Tentacruel at level 30.
Tentacool evolves into Tentacruel at level 30.
Tentacool evolves at level 30 into Tentacruel.30
level 30
Tentacool evolves into Tentacruel at Level 30.
Tentacool evolves at level 30 in all games.
Tentacool evolves into a Tentacruel at level 30.
level 30
Tentacool evolves on Lvl. 30 into Tentacruel.
It evolve in level 30 into a Tentacruel
Starting at lvl 30