This article is about a/an recurring plot element in the Kamen Rider Series.
In certain Kamen Rider Series, there are Riders who have access to a default form before they alternate between their Main Forms. Usually the Rider's default form is commonly used along with the other Main Forms, while some other riders include a base that gives access to alternate forms that offer slight advantages over the base form, such as added strength in return for lowered speed, etc.

The combat capabilities of Base Forms vary. While some riders (Agito, Ixa, Accel, Fourze, and Beast) are perfectly capable of holding their own in their Base Forms, others (Amazon, Kuuga, Ryuki, and Den-O) Base Forms are rather weak in comparison to their other forms.

Kamen Rider Kuuga

  • Kamen Rider Kuuga
    • Growing Form - Weak form Kuuga first accesses before he becomes strong enough to access his main forms

Kamen Rider Agito

Kamen Rider Den-O

  • Kamen Rider Zeronos
    • Plat Form - Zeronos' base suit prior to his chest armor and mask attaching

Kamen Rider Kiva

  • Kamen Rider Ixa
    • Save Mode - Ixa's default form before activating Burst Mode, as well as a the only form of the earlier version of Ixa

Kamen Rider W

  • Kamen Rider Accel - Accel is his normal form by default before transforming into Bike Form

Kamen Rider Fourze

Kamen Rider Wizard

Kamen Rider Gaim

  • Kamen Rider Gaim
    • Ride Wear - Gaim's undersuit before Armor Parts attach
      • Jimber Ride Wear - Gaim's undersuit in a Jimber form
      • Kachidoki Ride Wear - Gaim's undersuit in Kachidoki Arms
      • Kiwami Ride Wear - Gaim's undersuit in Kiwami Arms. Only exists in the Arms Change toyline

  • Kamen Rider Duke
    • Genetic Ride Wear - Duke's undersuit before Armor Parts attach

Kamen Rider Drive

  • Kamen Rider Drive
    • Type Speed Pre-Tire - Type Speed before the Type Speed Tire is attached
    • Type Wild Pre-Tire - Type Wild before the Type Wild Tire is attached
    • Type Technic Pre-Tire - Type Technic before Type Technic Tire is attached
    • Type Dead Heat Pre-Tire - Type Dead Heat before the Type Dead Heat Tire is attached
    • Type Formula Pre-Tires - Type Formula before the Type Formula Tires are attached
    • Type Tridoron Pre-Tire - Type Tridoron before the Type Tridoron Tire is attached
    • Type Fruits Pre-Tire & Hat - Type Fruits before the Type Fruits Tire is attached
    • Type High Speed Pre-Tire - Type High Speed before the Type High Speed Tire is attached

  • Kamen Rider Mach
    • Deadheat Mach Pre-Tire - Deadheat Mach before the Type Dead Heat Tire is attached

Kamen Rider Ghost

  • Kamen Rider Ghost
    • Transient - Ghost's base body before a Damashii is attached
      • Toucon Boost version - Transient after transforming into Toucon Boost Damashii
      • Grateful version - Grateful Damashii before the 15 Heroic Spirits unite and generate its helmet
      • Mugen version - Transient after transforming into Mugen Damashii

  • Kamen Rider Specter
    • Transient - Specter's base body before a Damashii is attached
      • Deep Specter version - Specter's transient after transforming into Deep Specter Damashii

Kamen Rider Ex-Aid

Kamen Rider Build

  • Kamen Rider Grease
    • Pre-Form - Grease's base body before the Variable Jelly finishes forming

Kamen Rider Zi-O