How to Get up Mud Slides in "Pokemon Emerald"by Matt Koble ; Updated September 22, 2017
The mudslides in "Pokemon Emerald" taunt new players, often hanging items just out of reach since you can't walk up these muddy spots. Fortunately, the game's Mach Bike makes riding up these obstacles a breeze.
The Mach Bike
"Pokemon Emerald's" bicycle shop, Rydel's Cycles, is found in Mauville City, where you'll get your third badge. Access Mauville City for the first time via route 103. Once in town, find the building with bicycles sitting outside and enter. Speak with the owner, who will give you a free bike of your choosing. While the Aero Bike is good for tricks, the Mach Bike gets better speed, enabling you to cycle up mudslides. You can come back to the bike shop and switch bikes at any time. Once you have the bike, equip it via the "Key Items" slot in your bag.
Riding Up Mudslides
While riding your Mach Bike, face the mudslide and ride towards it. You'll need to have decent speed built up to make it up the mudslide.