During the Main Story, Mario and Cappy will have to find Power Moons in order to power up the Odyssey to travel from kingdom to kingdom. After the Main Story is completed, Mario can find and obtain additional Power Moons in order to unlock new Kingdoms and Costumes. In Seaside Kingdom, there are 52 Power Moons that Mario can find during the Main Story. Some of these Power Moons will not be able to be found and obtained when first entering the kingdom; some Power Moons can only be obtained (even if listed below) after the main objectives have been completed in Seaside Kingdom. (Even more will appear after the Main Story is completed.)
Seaside Kingdom Power Moons & Mission Titles (Main Story)
Seaside Kingdom Power Moon 01 - The Stone Pillar Seal
Seaside Kingdom Power Moon 02 - The Lighthouse Seal
Seaside Kingdom Power Moon 03 - The Hot Spring Seal
Seaside Kingdom Power Moon 04 - The Seal Above the Canyon
Seaside Kingdom Power Moon 05 - The Glass Is Half Full!
Seaside Kingdom Power Moon 06 - On the Cliff Overlooking the Beach
Seaside Kingdom Power Moon 07 - Ride the Jetstream
Seaside Kingdom Power Moon 08 - Ocean-Bottom Maze: Treasure
Seaside Kingdom Power Moon 09 - Ocean-Bottom Maze: Hidden Room
Seaside Kingdom Power Moon 10 - Underwater Highway Tunnel
Seaside Kingdom Power Moon 11 - Shh! It's a Shortcut!
Seaside Kingdom Power Moon 12 - Gap in the Ocean Trench
Seaside Kingdom Power Moon 13 - Slip Through the Nesting Spot
Seaside Kingdom Power Moon 14 - Merci, Dorrie!
Seaside Kingdom Power Moon 15 - Bonjour, Dorrie!
Seaside Kingdom Power Moon 16 - Under a Dangerous Ceiling
Seaside Kingdom Power Moon 17 - What the Waves Left Behind
Seaside Kingdom Power Moon 18 - The Back Canyon: Excavate!
Seaside Kingdom Power Moon 19 - Bubblaine Northern Reaches
Seaside Kingdom Power Moon 20 - Wriggling on the Sandy Bottom
Seaside Kingdom Power Moon 21 - Glass Palace Treasure Chest
Seaside Kingdom Power Moon 22 - The Treasure Trap Hidden in the Inlet
Seaside Kingdom Power Moon 23 - Sea Gardening: Inlet Seed
Seaside Kingdom Power Moon 24 - Sea Gardening: Canyon Seed
Seaside Kingdom Power Moon 25 - Sea Gardening: Hot-Spring Seed
Seaside Kingdom Power Moon 26 - Sea Gardening: Ocean Trench Seed
Seaside Kingdom Power Moon 27 - Seaside Kingdom Timer Challenge 1
Seaside Kingdom Power Moon 28 - Seaside Kingdom Timer Challenge 2
Seaside Kingdom Power Moon 29 - Found on the Beach! Good Dog!
Seaside Kingdom Power Moon 30 - Moon Shards in the Sea
Seaside Kingdom Power Moon 31 - Taking Notes: Ocean Surface Dash
Seaside Kingdom Power Moon 32 - Love by the Seaside
Seaside Kingdom Power Moon 33 - Lighthouse Leaper
Seaside Kingdom Power Moon 34 - Good Job, Captain Toad!
Seaside Kingdom Power Moon 35 - Ocean Quiz: Good!
Seaside Kingdom Power Moon 36 - Shopping in Bubblaine
Seaside Kingdom Power Moon 37 - Beach Volleyball: Champ
Seaside Kingdom Power Moon 38 - Beach Volleyball: Hero of the Beach!
Seaside Kingdom Power Moon 39 - Looking Back in the Dark Waterway
Seaside Kingdom Power Moon 40 - The Sphynx's Underwater Vault
Seaside Kingdom Power Moon 41 - A Rumble on the Seaside Floor
Seaside Kingdom Power Moon 42 - A Relaxing Dance
Seaside Kingdom Power Moon 43 - Wading in the Cloud Sea
Seaside Kingdom Power Moon 44 - Sunken Treasure in the Cloud Sea
Seaside Kingdom Power Moon 45 - Fly Through the Narrow Valley
Seaside Kingdom Power Moon 46 - Treasure Chest in the Narrow Valley
Seaside Kingdom Power Moon 47 - Hurry and Stretch
Seaside Kingdom Power Moon 48 - Stretch on the Side Path
Seaside Kingdom Power Moon 49 - Secret Path to Bubblaine!
Seaside Kingdom Power Moon 50 - Found with Seaside Kingdom Art
Seaside Kingdom Power Moon 51 - Seaside Kingdom Regular Cup
Seaside Kingdom Power Moon 52 - Peach In Seaside Kingdom
Additionally, there will be 19 Post Game Power Moons that can be found and obtained in Seaside Kingdom.