8 hour Los Angeles layover – going to the beach?

Yes.

Here’s how I’d do it. The closest beach is Playa del Rey – it’s quite and non-commercial, you’ll have to walk for 5-10 minutes to find a coffee or an ice cream, but it’s nice.

Take the free parking shuttle to The Parking Spot: http://www.theparkingspot.com/locations/locations.aspx?ID=22

That will take you to Westchester. Eat at In’n’Out, or buy snacks from Trader Joe’s, or have German beer and Swiss/German food at Chalet Edelweiss (food is a touch pricey, but interesting).

Walk to the corner of Manchester and Sepulveda (about 3 blocks North, by Trader Joe’s), and catch the 115 bus towards the beach. Note that not every 115 goes all the way to the beach. The timetable is here: http://www.metro.net/riding_metro/bus_overview/images/115.pdf

Hang out at the beach, and then catch the bus back. Be careful, because the buses are only about every hour. If you’re in trouble, the worst case scenario is walking a mile and a bit back up the hill to Sepulveda, where you can catch the Big Blue Bus number 3 to the LAX bus center (described by @choster).

A visit to the beach is certainly possible. In fact, LAX itself is situated on the coast, but the roads from the terminals are on the inland side, making it a bleak 5 mile/8km walk one-way to Playa Del Rey— and I would not recommend either the activity or the destination.

Keep these things in mind:

1. The U.S. does not have outbound passport control, but as security screening can get backed up, I do recommend returning to the airport no less than two hours before your flight. If your bags have not been checked through, you will need time to recover them and check them.

2. It is not possible in most of Los Angeles to hail a cab on the street, so do not expect to be able to take a taxi you have not called for in the city. Neither are taxis in LA cheap; expect to pay around $50 each way including tip and airport surcharge to get from the terminal at LAX to Santa Monica pier. On the other hand, since you are traveling in a group, a taxi may be worth it to save waiting and walking time, and to avoid getting lost. For example, with a taxi, you could probably see both Santa Monica and Venice, go to Marina Del Rey (closest beach to LAX, if you actually plan to get in the water and want to maximize that time), or even catch an ocean view from Malibu or Pacific Palisades.

3. Buses are inexpensive and relatively plentiful in Los Angeles, but their schedules can be unreliable due to heavy traffic congestion. There is no train or tram service convenient to the beaches, either (and the Metro Green Line which almost-but-not-quite reaches LAX is something of a white elephant).

   For public buses, take the C shuttle from lower level roadway outside the terminals to the LAX Bus Center; from there you have a few options. Most of the north-south buses from here run along California State Route 1 (Pacific Coast Highway), but this section of PCH is inland from the coast, so you’ll either need to transfer to an east-west bus to get to the beach, or walk about 1-1½ mi (1.6-2.4 km), which will cut into your oceanfront time.

Now, with that preamble out of the way, my suggestions on the beaches:

• Venice Beach, north of LAX, is famous for its ocean walk scene rather than its actual beach. The scene has gentrified in recent years, but you will still see the street performers and the Muscle Beach Venice enthusiasts and some of the seedy… I mean, "funky"… old shops. You can take the northbound Big Blue Bus 3 or better the Big Blue Bus Rapid 3 if available (cash fare $1) and alight at Rose Ave. From there it is a little under a mile to the north end of Venice Beach on the Ocean Front Walk. You can rent bicycles from Boardwalk Skate or another of the shops there if you want.

  Walking south on the Ocean Front Walk about another 1½ miles will take you to the pier and Washington Blvd, from which you could walk another 1½ miles inland back to Lincoln Blvd and catch the southbound Big Blue Bus 3.

• Directly north of Venice Beach lies Santa Monica. Stay on Big Blue Bus 3 another 10 minutes or so past Rose Ave and alight at Colorado Avenue or Broadway. From there, walk west past (or through) the shopping center and you will find Santa Monica Pier and a variety of shops and eateries. You will also pass the Third Street Promenade shopping district. Santa Monica has gentrified to a greater degree than Venice, but there is just as much to see and do here, for one thing, the roller coaster in Pacific Park.

• To the south, Manhattan Beach is a wide, sandy beach south of LAX popular with surfers. It is less touristy here than Venice or Santa Monica. Take Metro Local 232 bus ($1.50 cash fare) about 25min south, alight at Manhattan Beach Blvd, and just walk west about 1mi/1.6km to reach Manhattan Beach Pier. If you stay on 232 south, you will reach quiet Hermosa Beach, and still farther Redondo Beach and its pier, but at that point you’ll have spent an hour just getting there, and the South Bay cities are not much to look at.