My single color marine lighting kit did not come with a switch. Is this something I would need to purchase separately?Updated 3 months ago

Yes, that is correct. The Single color Marine Kits do not come with any form of switch. Most boats have Auxiliary switches that can have 12 volt aftermarket accessories such as the kit wired into them. If your boat does not have that as an option, a waterproof switch would then need to be purchased for your application.