The man raised eyebrows during his bus journey to Manchester, England on Monday when he was seen with the animal draped around his neck and mouth.
A traveler who witnessed the incident told the Manchester Evening News that she initially believed the snake was "a really funky mask" until it started slithering around the handrails.
"It was definitely entertaining," she said.
Photos of the incident published online show that the unidentified man was not wearing a mask under the large brown serpent.
"This needn't be a surgical mask ... passengers can make their own or wear something suitable, such as a scarf or bandana," the representative said in a statement.
"While there is a small degree of interpretation that can be applied to this, we do not believe it extends to the use of snakeskin -- especially when still attached to the snake."