For the vast majority of waterproof jacket repairs, we recommend using Tenacious Tape. Gear Aid Tenacious Repair Tape comes in a neat little container and rolls out to 50 cm x 7.5cm. Depending on the jacket and the tear, you can place the tape on the inside (where the coat should be cleaner and less tape shows) or the outer. For the best level of protection put tape on both sides.
Once applied, the tape has several advantages over other more traditional DIY repairs (i.e. duct tape). It leaves no residue on the applied surface yet is very sticky, lightweight/malleable and its colour matches your jacket with a matte finish.
Along with waterproof jackets, you can also use the tape to repair rucksacks, tents, sleeping bags, waterproof trousers, tarps and even air mats.