score:9
The easier by far would be to rent a car.
Looking at the one-way rental prices between LAX (Airport) and San Diego, for March 31st, from Noon to 6PM (you could go shorter, LAX-SAN is a 2h drive)
From airport-to-airport Avis quotes ~$150 for a Camry or similar, and RentalCars.com has an entry for a Ford Focus for $120
From LAX to the Cross Border Xpress, Budget quotes me $97 for a Kia Rio and ~$100 for a Jetta/Camry or similar
By public transport :
Greyhound doesn't appear to do LA to San Diego
They don't from LAX but from Union Station, they do (look on their site)
Upvote:5
When we went from LAX to San Diego last year, we took an Uber. It was reasonably cheap and comfortable. Depending on the size of your group, you should check the size of the ordered car carefully, as a lot of luggage might not fight if all seats are taken by passengers.
Pro-tip: The Uber is much cheaper if you order it not directly from the airport, but take one of the airport busses first to get some distance from the airport.
Upvote:5
I figured easiest would be getting the Amtrak from LA Union Station to San Diego, but have discovered all trains on March 31 are carry on only, no checked luggage (we have 3 suitcases in addition to all our carry on bags)
That just means "no porters", you'll have to DIY-muscle your bags onto the coach yourselves.
Amtrak doesn't care about baggage (or weight for science reasons*). Plenty of room.
The real winner here is the Tijuana Trolley, which goes directly from the San Diego Amtrak (Santa Fe station) to the border crossing at Tijuana. One seat ride, $2.50 fare, huge asterisk. That is just regular old suburban public transit, obviously no porters. And your party will take a ridiculously outsize amount of space compared to actual commuters, but that happens a lot on that trolley. Just don't do it during the outbound commute (4-7 pm).
Such an elegant solution to that transportation link. San Diego really outdid themselves. Amtrak is actually fairly hard to get to from LAX, but if you can find a more direct way to get to San Diego Amtrak ("Santa Fe station"), feel free to do it.
The huge asterisk: The Trolley uses a "proof of payment" system in which you must obtain some sort of ticket or e-ticket before you board. This is a limited-time typically 2-hour "pass" which entitles you to be on the system. Note that some tickets are sold "not activated" so you can pay now and activate later; these must be activated - don't forget!
Honestly, the app may be the path of least resistance, as otherwise they'll sell you a permanent physical transit card that only works in San Diego. The physical card doesn't require you to set up an account, you can do it "anonymously". However, each person needs their own card or app - one person can hold the cards, but there must be a separate card or app for each person. There is no way to put 2 activated fares on one card or app.
Fare inspectors will randomly check trains and give $300 fines for fare evasion to honest newcomers looking for someone to pay. I'm not kidding. That's real. It's a Federal program subsidized by Ford and Toyota to make sure no new riders ever take public transit, OK I'm kidding about that. But really, it does seem like that.
Wow, this just turned into a warning against the Tijuana Trolley.
* Trains don't have induced drag thanks to Mr. Timken, so weight does not add any significant fuel cost. (actually it takes more fuel to haul an empty coal train than a full one, since the coal acts as a fairing to keep the empty hoppers from scooping air).
Upvote:9
Rome2rio pointed me towards CBX aka Cross Border Express advertise a number of shuttle services, including from Los Angeles to Tijuana.
There are 5 trips on March 31st, taking between 3h40 and 6h, with prices between $30 and $35.
Greyhound also operates services from LA Union Station to Tijuana and San Diego.
Flixbus have services from various locations in LA to various locations in San Diego.