Mix marinade ingredients together in a bowl and add fish. Place covered in the refrigerator to marinate 2 to 4 hours.
Preheat grill to medium-high or prepare coals. Remove fish from marinade (which you can discard) and season with salt. Grill approximately 3 minutes on the first side. Reduce heat to low or move from direct heat, flip to the other side and grill another 3 minutes, depending on thickness of the swordfish steaks. A skewer or small knife should go through with ease.