Most of these have schedules on their websites -
California Dive Boats : The Official Page
not sure how many are a month out. Your best bet is probably someone going to the Northern Channel Islands or maybe Catalina, Most list the Kelp dives separately but anything to Anacapa Island is a possibility. I don't know of anyone doing that as a day trip though.
If you don't mind a drive, Lois Ann or probably Waterhorse Charters could be divng the Point Loma Kelp beds then also. About 3+ hours to San Diego depending on the trafic thru Orange County.
The LA boats mostly leave from Long Beach/San Pedro or the Ventura/Santa Barbara to the north - which could be a 2 hr drive with traffic. Get an LA traffic app - some have real time updates. Any freeway going past downtown LA will likely be a parking lot most mornings. Sometimes into Long Beach/San Pedro also - it's the regional container port.
There's also a Possibility at Los Coronados Islands -there at least if there's no kelp, the Sea Lions will provide the entertainment. Waterhorse goes there and handles the day Visa since it's Mexico. I believe you'll need to bring your Passport also. If they are going, I might get a cheap room near the harbor and overnight the night b4 - they could be leaving as early as 4am - it's a pretty long ride south. Could be a 2 day trip also - likely on the weekend
You;re not going to have a lot of options W-TH - some boats don't work TH to prep for the long weekend trios - Fri-Sun is pretty common
check with drbill here on SB - he's a marine biologist and lives on Catalina and will have an idea of whether i's worth the trip out there. Some years the Kelp is sparse everywhere.
