Different methods of plasma formation have been studied in spherical tokamaks (ST). In inductive methods, breakdown and formation of ST plasma are achieved through the application of an electric field produced by a rapid change of currents in poloidal field coils, in the central solenoid or by using internal electrodes. In non-inductive methods, breakdown and formation of ST plasma are achieved by the application of radio frequency (RF) power, neutral beam injection or other ionization and current drive techniques. A combination of these methods is often used. Inductive methods utilizing flux from the central solenoid have limited performance as there is limited space for the central solenoid in STs, so methods not using the central solenoid flux are of special interest. In this paper we discuss different methods developed and used on the START and MAST STs at Culham; in particular, direct induction and electron cyclotron resonance preionization assisted formation are discussed in detail. These experiments have been performed at different RF frequencies and results of these studies are compared with the theory. Other methods, for example, the merging–compression and the double-null merging, are mentioned and prospects of different formation methods for future STs are discussed.