Yesterday, The Flight Deal posted a $327 Delta fare for LAX-SJU, San Juan, Puerto Rico. That fare caught my eye and this morning I see there is also availability for United Airlines flights on this route at $323 to $327 round trip.
These low fares start for departures August 31 and run to December 9, 2015. There is availability sporadically on every day of the week, except Sundays. You can even mix and match fares flying United and Delta the other direction for $182 to $187 one-way. Typical routing is via New York JFK or Newark EWR.
Delta Airlines Los Angeles LAX – SJU San Juan, Puerto Rico
$326.60 Saturday, November 7 – Friday, November 13
United Airlines Los Angeles LAX – SJU San Juan, Puerto Rico
$326.60 Wednesday, September 2 – Sunday, September 6