The Rotom Bike is the quickest way of getting around the Galar Region in Pokemon Sword and Shield. There's a few upgrades you can purchase for the bike, one of which will actually let you ride it on water. In our complete Pokemon Sword and Shield bike upgrades guide, we'll be providing you with all the details you need on upgrading the Rotom Bike as easily as possible.
Sword and Shield Bike Upgrades
You'll notice that if you hold down B while riding the Rotom Bike, you get a temporary speed boost. You'll have to manually recharge this ability by riding around on the bike for roughly 5 or 6 seconds after a boost, but this is vital in winning any of the time trials that are scattered around the wild area just south of Motostoke.
To upgrade the boost feature of the Rotom Bike, you'll want to find the Pokemon Nursery in this wild area. Check your map, and go to the area just east of Motostoke, where you should see a small building near the eastern edge of the map. This is the Pokemon Nursery, one of several in Sword and Shield.
Approach the Pokemon Nursery, but don't enter it. Instead, speak to the trainer dressed in cycling gear that's stood just to the left of the building. He'll brief you on the Rotom Races, time trials that you can enter to win items. But he'll also offer to upgrade the top boost speed of your Rotom Bike for 1,000 Watts.
If you don't already know, you acquire Watts in Pokemon Sword and Shield by approaching glowing husks on the ground, like the one pictured just below. If the husk isn't glowing too brightly, you'll be granted 50 Watts, but if the husk is glowing, and you can initiate a Dynamax battle there, you'll be automatically granted 300 Watts for engaging with it.
Take these Watts to the trainer by the Pokemon Nursery, and he'll increase the top boost speed of the Rotom Bike for 1,000 Watts. However, he can also increase the boost speed of the bike again, a second time, this time for 3,000 Watts. Note that both upgrades stack on top of one another, and will remain with your Rotom Bike for the rest of the game.
How to Ride the Rotom Bike on Water
While you're exploring the wilds of Pokemon Sword and Shield fairly early on, you might be wondering how you can traverse the small lakes. There's Pokemon on them, after all, so it's only natural to wonder how you can get close enough to catch them.
Turns out, this is another upgrade for the Rotom Bike. You'll need to advance to Route 9 in Sword and Shield by progressing the main story of the game, where you'll eventually come to a scientist, and two Team Yell goons standing before an icy lake.
Approach them, and the scientist will tell you to defeat the two Team Yell grunts in battle. After you've done this, the scientist will gladly upgrade your Rotom Bike so it can now glide smoothly along the surface of the water. Although Team Yell can get around by riding on a Drednaw, you're unfortunately restricted to the Rotom Bike for traversing water.
This might be it for our guide on bike upgrades in Sword and Shield, but we've got plenty more guides to come. For now, you can check out either our guide on Charmander in Sword and Shield, or our page on all the Ballonlea Gym quiz answers for more.