Seaside Island

Bygone Island is a major location in the Sonic Boom series and where Sonic and his friends live. The island is shown to have various regions with climates and environments different from one another, such as a region of ice and snow neighboring a tropical forest.

Bygone Island is frequently attacked by Dr. Eggman from his his lair which lies just off the coast of the island.

Locations
The island has various regions, often different from one another, such as tropical forests, frigid and a desert canyon.

Sonic's Shack
Sonic lives in a simple hut-like shack on the beach, which does not contain many commodities besides a hammock and a table.

Tails' House
Tails lives on a hill at Seaside Coast in a hut, with windmills and waterwheels that he has created for sustaining energy for living. It is not too far from Sonic's Shack.

Amy's House
Amy lives in a round house by the ocean built on wooden platforms. It features a small garden with a lookout nearby.

Stick's Burrow
Stick lives in the jungle area not too far from the town at Seaside Coast. She made her home into the small hill and it is where she feels most safe from her paranoia. She has decorated her home with the collection of various items she has found.

Knuckles Hangout
Knuckles lives in a cave located at the Scrapyard where he exercises regularly to keep in shape.

Town
The town is where the inhabitants of the island live and often targeted by Doctor Eggman's attacks, such as the Anti-fire Bot or a raid from the Danger Co. Deadly Equipment warehouse. It also has food court and a pet shop where Stick found Cluster Bot (near the pet shop, in the rubbish) and adopted it as her own

Sonic Boom: Rise of Lyric
Bygone Island is the second major location you go to in Sonic Boom: Rise of Lyric. It is here you find Mayor Fink who requests you to fix up the town in similar manner that you would at Cliff's excavation site. It is also here you meet Sticks the Badger (for the heroes, the very first meeting) where she requests Sonic to find "shinies" for Princess Crowns.

Perci also lives on the island, her family have defended the island and asks Sonic and his friends to activate the tower defenses around the town in order to protect the island from Lyric's invading forces.

Other areas of the island beyond the town is the semi-dormant volcano which leads to Crater Lake. Another outside of town leads to the farmlands where Slowpoke Island is beyond. Along the beaches outside the front of the town is Coral Bay which has the entrance of the Ancient Template and another secluded beach which leads to Creeper Gorge. Near the starting point of Bygone Island is a tower where you can access Sky Citadel.

North-East of Bygone Island is the desolate waste where Lyric chose his lair.

Sonic Boom: Shattered Crystal
Six major locations of the island are introduced. Sonic Boom: Shattered Crystal confirms that Sonic and his friends live on Seaside Coast of the island while Knuckles live in the Scrapyard which is the next location over from Seaside Coast. Other areas introduced are Shadow Canyons, Ancient Ruins, Volcanic Crater and above the island Cloud Sanctuary.

Trivia

 * As of yet, the island is not actually named in the TV series. However, it is identified in Sonic Boom: Rise of Lyric as it is one of the hub worlds in the game.
 * Bygone Island, or at least the whole overworld in Sonic Boom: Shattered Crystal is also unnamed.