Print the page with the gift card number and security code (PIN)
Use the gift card number and security code (PIN) on southwest.com, at any Southwest Airlines ticket counter, or by calling Reservations at 1-800-I-FLY-SWA

Redemption Online at southwest.com:

After a Customer has selected all flights and inputs the Passenger information, the Customer will then have to input the payment information.
To use a Southwest gift card as a form of payment, the Customer should click on the 'Apply Travel Funds' under the 'Do you want to apply travel funds?' section.
The Customer will input the gift card number and security code (PIN) in the designated location and click the button 'Apply Funds.’
This will deduct the amount on the gift card from the total.
If a balance is left the Customer will then have to use another form of payment to pay the remaining balance.

Southwest® eGift Card Balance Check

Southwest® eGift Card Balance