Southwest Airlines operates out of Terminal 1 at Harry Reid International Airport (LAS) in Las Vegas. Specifically, Southwest flights depart and arrive at Terminal 1 in the B and C concourses. Terminal 1 is the main domestic terminal at LAS, and it has gates A, B, C, and D. Southwest uses gates in the B and C concourses, where travelers can find various shops, restaurants, and other amenities. So if you are flying Southwest in Las Vegas, you will use Terminal 1, particularly the B and C gates. Terminal 3 is not used by Southwest Airlines at LAS. This setup allows easy access to Southwest check-in and gates without leaving the TSA-secure area of Terminal 1. Let me know if you want additional details about Terminal 1 or Southwest flight amenities in Las Vegas.