Sonic Adventure upgrades are special upgrades available in Sonic Adventure and its remake that are given to Sonic, Tails, Knuckles, Amy, Big, and E-102 Gamma. Obtaining an upgrade will allow a character to perform a technique that they could not do before. Most characters, with the exception of Sonic and Big, receive two upgrades throughout their journey.
Sonic the Hedgehog
Sonic receives three different upgrades throughout his quest.
The Light Speed Shoes are Sonic's first upgrade.
- Purpose: Allows Sonic to use Light Dash, enabling him to race across a trail of rings.
- Location: Station Square sewers. After completing Windy Valley, go to the city hall section and drop down the open manhole in the road. The Light Speed Shoes are in this underground section.
- Requirements: Finished Windy Valley.
- Required For: The many vertical-ring-paths that Sonic runs into throughout his story. Indeed, you have to use the Light Speed Dash to get out of the sewer you pick the shoes up in.
The Crystal Ring is Sonic's second upgrade.
- Purpose: Allows Sonic to charge the Light Dash faster.
- Location: Station Square hotel. Climbing the stairs reveals a landing with two buttons; one to open a door on the other side of the lobby, and the other to generate a trail of rings leading to it. The Crystal Ring hides beyond that door, but it can only be reached in time by using the Light Dash.
- Requirements: Light Speed Shoes.
- Required For: Nothing--it's purely a novelty item to make Sonic's life easier when confronted with otherwise tedious charge times.
The Ancient Light is Sonic's final upgrade.
- Function: Allows Sonic to perform Light Speed Attack.
- Location: Mystic Ruins Adventure Field. Near the entrance to the Red Mountain stage in the Angel Island section of the ruins. The Ancient Light is sitting on a rock to the left.
- Required For: Destroying the Kiki in the cage that locks Red Mountain's stage entrance.
Miles "Tails" Prower
Tails receives two different upgrades throughout his quest.
The Jet Anklet is Tails' first upgrade.
- Function: Increases Tails' speed while flying.
- Location: Station Square Adventure Field. Near Twinkle Park, there is an area that leads to the sewer underneath. Inside, there will be a small opening in the ceiling. Fly up in there and the Jet Anklet is right inside.
The Rhythm Badge (Rhythm Brooch in Japanese) is Tails' final upgrade.
- Function: Allows Tails to use endless, consecutive tail attacks simply by holding the button.
- Location: Echidna Civilization. This is the only upgrade that is obtained in an area that cannot be visited again. Therefore it is impossible to leave the area without obtaining the upgrade. It can be found on the left side of the Echidna Civilization.
Knuckles the Echidna
Knuckles receives two different upgrades throughout his quest.
The Shovel Claw is Knuckles' first upgrade.
- Function: Allows Knuckles to dig in the ground.
- Location: Mystic Ruins Adventure Field. Near Tails' Workshop there is a cave. This cave also leads to the Chao Garden. There will be a tunnel on the left. Entering it will trigger a trap which locks Knuckles inside. The Shovel Claw will be in that cave. They are also the only means of escape.
The Fighting Gloves are Knuckles' final upgrade.
- Purpose: Allows Knuckles to use Maximum Heat Knuckles Attack. The move seems to be a counterpart to Sonic's Light Speed Attack.
- Location: Mystic Ruins Adventure Field. It can be found near Big's house, on a ledge just above.
Amy receives two different upgrades throughout her quest. Interestingly, both upgrades are found in the exact same place.
The Warrior Feather (Sage Feather in Japanese) is Amy's first upgrade.
The Long Hammer is Amy's final upgrade.
- Purpose: Upgrade to the Piko Piko Hammer, making it longer and changing its overall appearance.
- Location: Egg Carrier Adventure Field. Amy must beat 3,000 points after the Egg Carrier has fallen from the sky (this must be done before completing Final Egg, otherwise the upgrade will only be available the next time the Adventure Field is available, after Amy's story's end).
Big the Cat
Big, interestingly, has the most upgrades of all the characters, though most of them are lure upgrades. There are a total of six upgrades.
The Power Rod is Big's first upgrade.
- Purpose: Upgrade to Big's fishing rod. Allows a longer casting distance.
- Location: Mystic Ruins Adventure Field. It's in Big's house under his bed.
The Life Belt is Big's second upgrade.
- Purpose: Allows Big to float in water. Pressing the button will allow Big to dive.
- Location: Mystic Ruins Adventure Field. Just before the entrance to the Ice Cap stage. The Life Belt is sitting next to the icy lake.
Big receives a series of difference upgrades for his fishing lure. Each one will allow him to catch bigger fish. The order of which they are obtained does not seem to matter.
- Lure upgrade 1 location: Station Square Adventure Field. Near where Tails finds his Jet Anklet. It is sitting in the water just under the same opening.
- Lure upgrade 2 location: Mystic Ruins Adventure Field. In the jungle area with Big's house and the ruins of the Echidna temple. There will be a secret room hidden near Big's house. It is much easier to find in Sonic Adventure: DX thanks to the new map function on the menu screen.
- Lure upgrade 3 location: Ice Cap Action Stage. This is the only upgrade to be found during an Action Stage. Big must climb up the ice stairs until he finds a small pool that will lead to another area. In that area, there will be dinosaur bones on the ice. There should be a spot of thin ice that Big can break through. Dive down and you will see a dinosaur head at the bottom. The lure will be right in the dinosaur's eye.
- Lure upgrade 4 location: Egg Carrier Adventure Field. In the holding cell area where Amy was taken. It will be in the cell closest to the door.
E-102 Gamma will receive two different upgrades throughout its journey.
The Jet Booster is Gamma's first upgrade.
- Purpose: Allows Gamma to hover by holding down the button.
- Location: Egg Carrier Adventure Field. In the main room of the Egg Carrier with the entry way to the holding cells and the Hot Shelter. The Jet Booster will be on the other side of the door to the left of the room.
The Laser Blaster is Gamma's final upgrade. Interestingly, Tails and Eggman will receive the same upgrade in Sonic Adventure 2.
- Purpose: Upgrade to Gamma's gun. Gives it a wider attack pattern.
- Location: Egg Carrier Adventure Field. It will been in the room opposite to the room where the Jet Booster is obtained. It cannot be obtained when the ship is in Sky Deck mode as the room will be filled with water.