Continuous-wave operation of InGaN green laser diodes (LDs) on semi-polar {202 -1} GaN substrates with output powers of over 100 mW in the spectral region beyond 530 nm is demonstrated. Wall plug efficiencies (WPEs) as high as 7.0 ‒ 8.9% are realized in the wavelength range of 525 ‒ 532 nm, which exceed those reported for c-plane LDs. The difference in the WPEs between these two crystal orientations was found to become larger with increasing wavelength. These results suggest that the InGaN green LDs on the {202 -1} plane are better suited as light sources for applications requiring wavelengths over 525 nm. We also discuss the current status and the future prospects on the output power and the lasing wavelength of green semiconductor LDs compared with c-plane LDs.