The Southwest Airlines pet policy is as follows:
Small vaccinated domestic cats and dogs are accepted in the aircraft cabin.
Southwest Airlines will only carry pets in the cabin; pets are not permitted as checked baggage.
Pets are not allowed to travel in-cabin on international flights or any itinerary that includes an international flight.
Southwest Airlines does not accept pets (cats or dogs) traveling without a Customer.
Pets will be accepted on a first-come, first-served basis until capacity is reached. Six (6) pets are allowed per flight with a limit of one pet carrier per paying Customer traveling on the same flight. However, from time to time, circumstances may allow for more (or fewer) than six (6) pet carriers per scheduled flight.
For Customers traveling to Puerto Rico, specific requirements may apply.
Southwest Airlines does not transport pets to or from Hawaii.
At the airport find pet relief areas.
More information on the Southwest Airlines pet policy