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If you are a few thousand Rapid Rewards points short of a flight, buy the missing points while a discount is running, then book right away. If the flight leaves within hours and you cannot wait for points to arrive, use Southwest's Cash + Points option or pay the fare. Those are the two paths, and the rest of this guide helps you choose.

Start with the numbers

Southwest ties award prices to cash fares, and last-minute fares are usually the highest. Frequent Miler notes that the points needed rise with demand. Check the price now, since it may have moved since you last looked.

Write down:

• The points price for the flight.
• Your current balance.
• The cash fare.

The first minus the second is your gap. The third is your fallback.

Option 1: Buy the missing points

Southwest sells Rapid Rewards points for 3 cents each at the standard price and often discounts them. One Mile at a Time reported a sale from September 2 to October 2, 2026, with discounts of 35%, 45%, or 50% depending on the member, and Award Travel Finder listed a 50% discount running through October 29, 2026. Your account shows which offer, if any, applies to you.

The September sale discount required a purchase of at least 3,000 points. What that costs:

• At 50% off: about $45.
• At 45% off: about $50.
• At 35% off: about $59.
• At full price: $90.

Larger gaps, at 50% off:

• 5,000 points: about $75.
• 10,000 points: about $150.

According to One Mile at a Time, you can buy up to 60,000 points per day, with no annual limit.

Timing: allow time for the points to reach your account. Posting times vary, so don't buy with minutes to spare. If your departure is within a few hours, go to Option 2.

Check your Rapid Rewards points offer.

Option 2: Cash + Points

Southwest lets you pay for a ticket with a mix of cash and points. Nothing has to post first, so it works for last-minute trips.

The drawback is value. Frequent Miler says this option yields poor value per point. Use it when time is the constraint, not as a habit.

Option 3: Have someone else book it

Southwest lets members book award flights for other people. If a partner, parent, or bandmate has enough points, they can book your seat from their account, and you can settle up between yourselves.

This is usually better than asking them to transfer points to you, because Southwest charges a fee for transfers between members.

Option 4: Pay cash and keep your points

Sometimes the best top-up is none. Divide the cash fare by the points price. Frequent Miler benchmarks a Rapid Rewards point at 1.3 cents, and One Mile at a Time estimates 1.1 to 1.5 cents. If your flight gives you less than that per point, pay the fare, earn points, and save your balance for better use.

Which should you pick?

• Short by 3,000 points or less, with a day or more to spare: buy during a discount.
• If you have hours left: Cash + Points, or pay the fare.
• Someone you trust has points: ask them to book.
• Short by 10,000 or more: run the cash comparison first. A big purchase at 1.5 cents or more per point rarely beats paying the fare.

A worked example

These are illustrative numbers. A Friday flight costs $289 or 21,500 points. You have 19,000 points.

• Buy 3,000 points at 50% off: about $45 out of pocket. You fly for $45 plus taxes and keep 500 points.
• Pay cash: $289, and your 19,000 points stay unused.

Here the top-up is the obvious choice. It saves about $244 compared with paying the fare.

Change one number. You have only 6,000 points and need 15,500 more. At 50% off, that costs about $233, close to the $289 fare, and you would drain your balance. Paying cash and earning points on the trip is the better move.

Why points are useful for uncertain plans

Frequent Miler notes that Southwest award flights can be canceled with no fee up to 10 minutes before departure, and the points come back to your account immediately. One Mile at a Time adds that a canceled cash ticket becomes a travel credit for a future flight.

For a last-minute trip that might still fall through, a points booking is easier to undo. That is a real reason to top up even when the math is only slightly in your favor.

Small print

• Rapid Rewards points don't expire, so leftovers from a top-up will stay.
• Purchased points do not count toward the Companion Pass.
• Points.com processes the purchase, so your card will not treat it as airfare.
• Free checked bags now depend on your fare, status, or Southwest card. Include bag fees when comparing a Southwest fare with another airline's.

Top up your Rapid Rewards balance and book.

FAQ

What is the minimum number of Southwest points I can buy?

The recent discount applied to purchases of at least 3,000 points. Check your account for the current minimum.

Can I book a Southwest flight with points for a friend?

Yes. You can book award flights for others from your account.

Can I cancel a Southwest points booking?

Yes, with no fee up to 10 minutes before departure, and you get your points back.

Is Cash + Points a good deal?

Generally not on value, though it is useful when you are out of time.