You already know that, in general, the best time to shop to get the cheapest possible domestic airline tickets on all airlines is Tuesday afternoon, right?

But what about specific discount carriers like the popular Southwest Airlines? Here’s what you need to know to get the cheapest airline tickets with Southwest Airlines.

Always Compare Prices

Before you buy, check with an airfare comparison shopping site to be sure you’re getting the best price. If you go to any individual airline site to shop, you may miss out on better deals.

Southwest’s Click-n-Save Specials

Southwest files its Click-n-Save specials every Monday night in the 8pm domestic airfare distribution (there are 3 domestic airfare distributions each weekday: 10am, 1pm and 8pm), and it hits their reservation system in the wee hours of the morning the next day.

Tuesday Mornings

So Tuesday morning is one of the best times to shop, but there are some caveats — these specials typically include limited routes that Southwest wants to try and fill up, seat-wise for particular travel days. In other words, it is not (usually) an across-the-board sale.

Competitor Matching

Southwest normally matches competitors’ sales (which are usually filed Monday night at 8pm Eastern as well) and Southwest usually matches by the Tuesday 1pm domestic airfare distribution, which then hits their reservation system at approximately 3pm Eastern (these cheaper prices are typically pulled 3 days later on Thursday night).

Like all airlines, Southwest is very active in matching prices of their competitors who fly the same routes as they do on a daily basis (both nonstop and connecting flights). Just so you know, Southwest serves just under 70 cities, while the legacy airlines typically serve between 130-240 non-code share cities.

How to Stay on Top of Sales

One easy way is to stay on top of sales from all airlines is to follow our airline ticket deals blog which posts advertised sales for worldwide airlines on a daily basis (follow with a RSS reader if you have one or on Twitter @farecomparedeal).

If you have specific locations in mind, sign up for our realtime email airline ticket price drop alerts — no airline wants to be undercut so following all airlines on a route for your next trip is the best way to know exactly when to shop and buy (let us do all the heavy lifting).

Don’t Forget Facebook and Twitter

Southwest is also very active on Facebook (/Southwest) and Twitter (@SouthwestAir) and the airline will sometimes announce special deals on these channels at various times, and this is in addition to their blog and email communications.

If you have an issue, grab your smart phone and post on their Facebook page or tweet your problem — you’re likely to get a faster response as Southwest has PR people manning those social media channels full-time.

Bottom Line

So the best time to purchase tickets on Southwest varies, but a good rule of thumb is – again – shop Tuesday at 3pm Eastern, when the carrier has matched other airlines’ sale prices.