Dewgong is a Tier-3 Raid Water Ice boss with a raid boss CP of 12803. Dewgong is lacking in offence, but is decently bulky for a Tier-3 raid boss. Dewgong can be soloed relatively easily.

Max CP at Level 40 1985 | Max CP at Level 50 2245
ATK 139 DEF 177 HP 207
Weak To: Strong Against:
Electric Fighting Grass Rock Dragon Ground Grass Flying Fire Rock

Dewgong isn’t what you would call a useful PvE Pokémon, given the low stats. However, the low Attack and higher Defence/Stamina lend themselves well to PvP. Dewgong can be solo raided.

Best Dewgong Counters

The following Pokémon are best Pokémon to use against a Dewgong in Raid Battles:

# Pokemon Fast Move Charge Move Time to win Deaths
1. Thunder Fang Electric Wild Charge Electric 114.5s 2
2. Counter Fighting Aura Sphere Fighting 120.5s 2
3. Smack Down Rock Sacred Sword Fighting 121.9s 2
4. Rock Throw Rock Rock Slide Rock 124.2s 3
5. Smack Down Rock Rock Slide Rock 124.3s 3
6. Volt Switch Electric Thunderbolt Electric 125.8s 3
7. Charge Beam [thunderbolt] Wild Charge Electric 126.0s 2
8. Counter Fighting Dynamic Punch Fighting 131.3s 2
9. Thunder Shock Electric Wild Charge Electric 134.2s 3
10. Counter Fighting Dynamic Punch Fighting 135.1s 2
11. Smack Down Rock Rock Wrecker Rock 135.4s 3
12. Low Kick Fighting Focus Blast Fighting 137.7s 2
13. Volt Switch Electric Wild Charge Electric 138.4s 2
14. Vine Whip Grass Frenzy Plant Grass 129.5s 2
15. Vine Whip Grass Power Whip Grass 133.5s 2

You can see from the Pokémon listed that your best bet is to use strong Electric, Rock, and Fighting-type moves.  Zap zap zap.  Three or four good counters and you should be in a solid position to solo Dewgong.  If you’re unsure, or less confident one other reasonably prepared trainer should be enough to take it down.

Dewgong Move Sets

Dewgong has access to this set of moves as a raid boss:

Fast Moves Charge Moves
Frost Breath Ice Blizzard Ice
Iron Tail Steel Aurora Beam Ice
Water Pulse Water

Frost Breath, Blizzard, and Aurora Beam are all moves that could be a concern for Grass-types.

Iron Tail could cause problems for Rock types, however, it’s not anything to be very concerned over.