Seaside Hill is the first stage of Sonic Heroes.
The place is very tropical and takes place on grassy cliffsides and beaches. It seems to be an homage to Green Hill Zone from the original Sonic the Hedgehog, having checkered walls and palm trees. The stage that comes after it is Ocean Palace.
In 2P Play, the stage takes place at sunset and uses Sea Gate's BGM.
After receiving Eggman's message in the desert, Team Sonic somehow manages to get to the island coast and heads to the Whale Island to stop Eggman from taking over the world. Team Dark also appears at the scene to go to the Whale Island for Shadow to learn about his past, Rouge to get the Doctor's treasure, and for Omega to get revenge for being locked up with Shadow. Team Rose leaves the beach at Seaside Hill to go to Whale Island for Amy to find Sonic, Big to find Froggy, and for Cream to find Chocola. Team Chaotix arrive at the beach to collect ten hermit crabs to prove their detective skills to their client.
The following is a list of requirements to attain a rank for each mission with each team.
|Rank A||Rank B||Rank C||Rank D||Rank E||Mission 1|
|Team Sonic||60,000||55,000||50,000||45,000||<45,000||Head for the whale Island!|
|Team Dark||70,000||65,000||55,000||45,000||<45,000||Get to the whale Island!|
|Team Rose||48,000||42,000||35,000||28,000||<28,000||Get to the other side of the sea!|
|Team Chaotix||45,000||40,000||35,000||28,000||<28,000||Find 10 Hermit crabs!|
|Rank A||Rank B||Rank C||Rank D||Rank E||Mission 2|
|Team Sonic||50,000||45,000||40,000||32,000||<32,000||Get to the goal ring within 5 minutes!|
|Team Dark||7:00||7:30||9:00||11:00||>11:00||Defeat 100 enemies! (Time minutes.)|
|Team Rose||2:30||3:00||4:00||6:00||>6:00||Collect 200 rings! (Time minutes.)|
|Team Chaotix||35,000||30,000||25,000||18,000||<18,000||Find all 20 Hermit crabs!|
- The E3 demo's Seaside Hill layout still exists in the final game, but with no Rings and is only for Team Rose.
- The intro drums from Misty Lake's music in Sonic and the Black Knight are similar to the intro drums on the music from Seaside Hill.
- As Team Chaotix, it is possible to fly past the area with the last flower which teleports the player back to the start. This allows the player to access the cannon where Team Rose finishes while the placements are different from the first two teams, but when the player reaches the second bobsled area, the section will be blocked off and the player will be stuck there forcing them to restart or exit out of the stage as the bobsled object is not placed on that area for the team.
- A remix of Seaside Hill's music can be heard while fighting on Green Hill Zone in Dengeki Bunko Fighting Climax.
- On the music gallery, it is the 7th music track and named as "Seaside B-Field".
- Seaside Hill's music is one of the songs that can be played during events in Mario & Sonic at the London 2012 Olympic Games, Mario & Sonic at the Sochi 2014 Olympic Winter Games and Mario & Sonic at the Rio 2016 Olympic Games. It is also featured in Sega Superstars Tennis as an unlockable track for the Green Hill Zone court.
|STAGE 01 : SEASIDE HILL||Jun Senoue||2:42|
|1P (E3 Demo)||Jun Senoue||2:49|
|2P (E3 Demo)||Jun Senoue||3:25|
|Dengeki Bunko: Fighting Climax remix||N/A||5:06|