From Southwest’s FAQ—When the Federal law requires Customers to wear a mask (emphasis added):
Customers will be required to wear a mask over their nose and mouth at all times during their Southwest travel experience—while checking in, boarding, while in flight, deplaning, retrieving baggage; and any other time they may engage with a Southwest Employee or another Customer. Customers are required to wear a mask in order to board the plane.
The following are times when a Customer may need to briefly remove their mask:
When necessary for identity verification purposes such as during Transportation Security Administration screening or when asked to do so by our Employees or any law enforcement official
While eating, drinking, or taking oral medications. Prolonged periods of mask removal are not permitted for eating or drinking; the mask must be worn between bites and sips.
While communicating with a person who is hearing impaired when the ability to see the mouth is essential for communication
If, on an aircraft, wearing of oxygen masks is needed because of loss of cabin pressure or other event affecting aircraft ventilation
If unconscious (for reasons other than sleeping), incapacitated, unable to be awakened, or otherwise unable to remove the mask without assistance