Hi! I'm flying into Gatwick North Terminal from Canada on a US passport. I have 3 hours until my South Terminal departure to the Canary Islands. I think that means I have to go through customs, right? And then shuttle to the South Terminal?
These are separate one way tickets. I will fly without checking luggage. I plan to check in for my flight the day before, so won't be doing luggage nor checking in. Do you think I'll make it, and do you think I increase my odds by paying for the Premium Security and/or the Premium Passport Control?
As you are travelling on two separate tickets you will have to go through border control and then through Customs before being landside.
Unless you have a very lengthy inbound delay imo 3 hours is more than ample for transferring from Gatwick North to Gatwick South. The free shuttle takes less than 5 minutes and operates every every few minutes...and it's just a couple of minutes' easy walk from Gatwick South Arrivals to the shuttle.
Your outbound flight will close check-in around 40 minutes before departure...but if you have no checked bags and have already checked-in online and have your boarding pass that's pretty much irrelevant.
I don't think you'll have any problems at all making this transfer (barring extreme inbound delays) and I certainly wouldn't pay extra for 'Premium Services'. :-)
I'm not sure but i think you might need a transit visa seeing as you're coming landside.