This is a question we get on a weekly basis from our guests who don't have a rental car and want to go to Disneyland, which is located in Orange County. It is important to keep in mind that without a car, this trip takes a long time - as in 2+ hours each way. For this reason, we highly recommend spending 1-2 nights at a Disneyland area hotel (Anaheim) either before or after a stay in Los Angeles. If you are landing or leaving from LAX, one convenient and very affordable option to get to Anaheim area hotels is to use a shared shuttle van service like Prime Time Shuttle ($16 per person).
If you still want to make make it a day trip, below are a few options to consider:
By Public Transportation - total trip time of 2 hours each way ($3.50 per person, roundtrip)
Catch the 760 Metro Bus towards Lynwood at 4th/Beaudry (2 blocks from Jerry's Motel)
Get off at 7th & Flower and transfer to the 460 Metro Bus towards Disneyland
Alternatively, you can take the Amtrak Surfliner train from Union Station in Downtown Los Angeles (fare is $12-$22, depending on class), get off at the Fullerton Station, take OCTA bus #543 (toward Santa Ana - Harbor & MacArthur) and get off at the Disneyland (Harbor Blvd.) stop. The fare for this bus ride is $2 as of March 2016.
By Uber/Lyft or City Taxi - total trip time of 45-60 minutes
A taxi will cost approximately $100 each way including tip. An Uber/Lyft ride can cost up to 30% less, or even more if you travel while they are surcharging (i.e. rush hour, rainy weather, late night weekends, etc.), so just be sure to take a look at your estimated trip cost before booking a ride.
By Lux Bus Tour Bus - total trip time of 1 - 1.5 hours
Lux Bus America has a pickup location at the Westin Bonaventure Hotel, which is located 4 blocks from Jerry's Motel. As of March 2016, a roundtrip ticket costs $45 per person. You can also purchase Disneyland tickets directly through them. Just note this bus does return a little early, so you will not be able to stay until closing and you may have to miss fireworks shows (depending on schedules for that day - check the Disneyland Entertainment Calendar). However, it is the most convenient way to get from Downtown Los Angeles to Disneyland.
See links below for additional details:
Starline Tours also offers similar packages
Rent A Car For The Day
Car rentals can be very affordable and cost anywhere from $20-$50 per day for a compact car. You can easily reserve online and pick up at one of the nearby car rental companies located downtown, such as Enterprise-Rent-A-Car, which is located in the lobby of the nearby Westin Bonaventure Hotel. Parking at Disneyland costs $18 as of March 2016.