We report for the first time on the performance of 1300 nm waveband semiconductor disc lasers (SDLs) with wafer fused gain mirrors that implement intracavity diamond and flip-chip heat dissipation schemes based on the same gain material. With a new type of gain mirror structure, maximum output power values reach 7.1 W with intracavity diamond gain mirrors and 5.6 W with flip-chip gain mirrors, using a pump spot diameter of 300 μm, exhibiting a beam quality factor M2<1.25 in the full operation range. These results confirm previously published theoretical modeling of these types of SDLs. © 2014 Optical Society of America.