I believe you will need a passport for all trips heading out of SD now.
Since April is kind of before the season really gets going, I would call Fisherman's Landing (619) 221-8500 or Point Loma (619) 223-1627 and see what they have planned.
I have yet to have a bad experience with the SD overnight or greater boats. The day trip boats are pretty horrible because of the crowd-can be more than 50 people!
The 3 day and longer trips are really spectacular. The food is top notch, you learn a ton and get tons of fishing time. I really recommend that you someday take a long range trip.