- “Awww... I'm sick of swimming all the time. Is it ice-skating season yet?”
- —Penguin, Super Mario Galaxy 2
Cosmic Cove Galaxy is a galaxy in World 2 in Super Mario Galaxy 2. It is primarily a water-themed level, where players can freeze the water in the first mission to skate on the ice and up water falls, or swim through caverns to find key objects. Penguins such as Coach and Penguru appear as inhabitants of this galaxy, where they can assist players by giving them helpful hints. Common enemies here include Skeeters and Koopa Troopas, as well as underwater enemies such as Snoodles. This is the only galaxy in World 2 with two main missions. One of its levels, Catch That Star Bunny, makes Cosmic Cove Galaxy the only galaxy in the game that has a mission that involves catching a Star Bunny.
Planets/Areas
NOTE: Unless otherwise noted, all names are unofficial.
Cove Planet
Starting Area
Players land on a sandy shore whose only inhabitants are the Coach and a Koopa Troopa. Players need to use the Green Shell provided by the Koopa to swim through the next area. Many Snoodles are found inside the underground tunnel, and a Spiny Cheep Cheep can be found at the end of the tunnel.
Cosmic Cove
After players emerge from the tunnel, they appear in this vast area. The entire area is underwater except for some platforms and a tower. The Comet Medal is located inside one of the giant shells underwater. A jellyfish lurks underwater as well as many Skeeters striding on the water and Cheep Cheeps. There is a Hungry Luma here that will transform into the Holey Planet if fed 15 coins. Penguru can be found on one of these platforms. During the first mission, there is a switch that can freeze the water, allowing the player to traverse it with ease.
Twin Falls
This area consists of two large waterfalls. After freezing the water, players can Wall Jump up the waterfalls and onto the pieces of land on which they flow. A Power Star is located here during the "Twin Falls Hideaway" mission.
Cosmic Cavern
This part of the galaxy consists of an underwater sidescroller section with a few Penguins, Brick Blocks and Gringills in it. Many thorny flowers grow from the walls of this cavern. A Warp Pipe that leads to the Water Maze is found at the end.
Water Maze
This area has a body of water hovering in space, surrounded by several small black holes. All the liquid in the area forms a maze, with some platforms floating over the surface. Near the end of the area there are some red-framed tubes with large cubical water bubbles moving through them and a group of Star Bits forming a star in the background. Mines, Goombas, a Paragoomba and a Jammyfish can be found here. The player visits this planet to move around in a side-scroller to find a Key to free a Luma in the Starting Area.
Water Core Planet
This planet is a spherical rock with a large stone wall splitting both halves. Players arrive on bottom side of the planet full of Fizzlits here. There is also a Spin Drill that players must use to get to the other side of the planet. Here, there are some Micro Mecha-Bowsers which players must destroy to unlock the shield protecting a dust patch. After players use a drill on it, water comes out and floods the planet. Players have to swim to the platform where the Power Star is located.
Holey Planet
After players feed the Hungry Luma in the Cosmic Cove area fifteen coins, it transforms into this planet. It has a Star Bunny that challenges Mario to catch it. It also has a blue ! Switch that freezes the water if Mario pounds it. The player must be careful not to fall in the holes that lead to the black hole in the center of the planet and be wary of the Skeeters that lurk here.
Enemies
Missions
| Level | Image | Overview |
|---|---|---|
| Twin Falls Hideaway | 
|
Players need to traverse underwater. When they reach their destination, they need to hit a switch in order to freeze the water, where players can use the ice and frozen waterfalls of the Twin Falls as a platform to reach the Power Star. |
| Exploring the Cosmic Cavern | 
|
Players need to explore an underwater cavern to find a key to free a Luma trapped in a glass cage. |
| Catch That Star Bunny | 
|
Players need to catch a Star Bunny to win a Power Star. |
Green Stars
Green Star 1
Players should do the mission Twin Falls Hideaway. After players freeze the water and wall jump the Twin Falls, they should skip breaking the crystal for freeing the Power Star. Instead, they should jump off the edge of the cliff where the Power Star is to get the level's first Green Star.
Green Star 2
Players should do the mission Exploring the Cosmic Cavern. When players get to the Water Maze, they should look for a platform with a Goomba on it. The Green Star is to the right of the platform and needs careful precision and aim if players need to obtain it.
Green Star 3
Players should do the mission Exploring the Cosmic Cavern. Players should make their way back to the Water Maze. Player should swim to the top where the key is. After getting the key, players should go to the platform on the right and perform a Long Jump to the Green Star off to the left.
Music
Names in other languages
| Language | Name | Meaning | Notes |
|---|---|---|---|
| Japanese | 星の入り江ギャラクシー[?] Hoshi no Irie Gyarakushī |
Star Cove Galaxy | |
| Chinese | 星球海灣銀河[?] | Star Cove Galaxy | |
| German | Kosmobucht-Galaxie[?] | Cosmic Cove Galaxy | |
| Italian | Galassia Baia Stellare[?] | Stellar Bay Galaxy | |
| Spanish | Galaxia Gruta Gélida[?] | Icy Grotto Galaxy |