|Other Appearances||Mario & Sonic at the Olympic Winter Games|
Sonic & Sega All-Stars Racing
Sonic & All-Stars Racing Transformed
|Level Type||Tropical Island|
|Preceded by||None, first level|
|Proceeded by||Ocean Palace|
Seaside Hill is the first stage in Sonic Heroes and it's at a tropical island setting. This stage have the teams progressing through the hills and beaches. Also, teams must be careful not to fall into the water, as it will cost a life.
 Sonic Heroes
 Team Sonic
Team Sonic decides to pursue Dr. Eggman to prevent him from taking over the world, after receiving his message.
- Normal Mission - Head to the Whale Island.
- Extra Mission - Get to the Goal Ring within 5 minutes.
 Team Dark
Team Dark wants to pursue Eggman, but for different reasons. Shadow wants to know more about his past, Rouge wants Eggman's treasure, and Omega wants revenge for being sealed up in a chamber.
- Normal Mission - Get to the Whale Island.
- Extra Mission - Defeat 100 enemies.
 Team Rose
Team Rose wants to pursue Sonic, after seeing the hedgehog in the newspaper, along with Froggy and Chocola, who Big and Cream respectively, is trying to find.
- Normal Mission - Get to the other side of the sea
- Extra Mission - Collect 200 rings.
 Team Chaotix
A mysterious voice from their walkie talkie decides to test Team Chaotix, to see how well their detective skills are.
- Normal Mission - Find 10 hermit crabs.
- Extra Mission - Find all 20 hermit crabs.
 Other Appearances
 Mario & Sonic at the Olympic Winter Games
In Mario & Sonic at the Olympic Winter Games, a snow covered Seaside Hill appears in the Dream Event: Dream Alpine. Players must simply ski their way to the finish line.
 Sonic & Sega All-Stars Racing
There are three tracks in Sonic & Sega All-Stars Racing that are inspired from Seaside Hill. The three tracks are: Whale Lagoon from the Chao Cup, Lost Place from the Horror Cup, and Ocean Ruin from the Samba Cup.
 Sonic Generations
 Act 1
Act 1 is played as Classic Sonic, and this stage introduces underwater sections. The giant wheel chase from Ocean Palace also appears in this level at the end of the stage.
 Act 2
Act 2 is played as Modern Sonic and in this stage, Sonic can boost over the water on certain segments. There's also a section where you can use a vehicle similar to the original stage. Finally, the music in this stage mixes the themes of Seaside Hill and Ocean Palace.