We report the discovery of three transiting exoplanets by the SuperWASP survey and the SOPHIE spectrograph with mass and radius determined with a precision better than 15%. WASP-151b and WASP-153b are two hot Saturns with masses, radii, densities and equilibrium temperatures of 0.31^+0.04^_-0.03_M_J_, 1.13^+0.03^_-0.03_R_J_, 0.22^+0.03^_-0.02_rho_J_ and 1,290^+20^_-10_K, and 0.39^+0.02^_-0.02_M_J_, 1.55^+0.10^_-0.08_R_J_, 0.11^+0.02^_-0.02{rho}_J_ and 1,700^+40^ _-40_K, respectively. Their host stars are early G type stars (with magV ~ 13) and their orbital periods are 4.53 and 3.33 days, respectively. WASP-156b is a Super-Neptune orbiting a K type star (magV = 11.6). It has a mass of 0.128^+0.010^_-0.009_M_J_, a radius of 0.51^+0.02^_ -0.02 R_J_, a density of 1.0^+0.1^_-0.1_{rho}_J_, an equilibrium temperature of 970^+30^_-20_K and an orbital period of 3.83 days.