Fare of the Day: Baltimore, MD (BWI) to San Diego, CA (SAN) $159 RT, including all taxes on Continental Airlines.
This fare is part of the ongoing fare war between Continental/United, US Airways, and Delta. We reccomend that you book soon if interested, these little tiffs between carriers seem to have short shelf lives.
Travel any day of the week if available, 21-day advance purchase restriction. You must be flexible with dates to find this price but it is available, try looking for fall dates or toward the end of the 330-day travel period.
Also, keep an eye out for fares that arrive/depart Carlsbad (CLD), all though it is close to San Diego it is actually about a half-an-hour north of the city and will come up as an option on some itineraries.