When VFR, how do I know who to contact first, approach or tower?
My home airport is KFSD, class D, and I always contact approach first but it’s KFSD approach, not another airport. I asked the google and it seems there’s no clear distinction other than “it depends”
It all comes down to the type of airspace around the airport. Why is it that you always call approach heading into FSD? Do you feel as though you have to?
SBP is also a class D with no surrounding C or B airspace that you need to traverse to get there. Therefore, your only requirements for the radios are establishing 2-way radio communications with SBP Tower prior to entering the class D airspace. Approach never needs to know anything about you.
The AFD or even just the frequency area of airnav.com is a good source to find the name of the approach control as it will have it listed with the approach/departure frequency.