Service animals, such as guide dogs, may accompany persons with disabilities in San Mateo County Transit District facilities, on the vehicles operated by or for the district and on Caltrain.

The animal must be on a lead that does not interfere with other passengers in the vehicle, and be under the constant supervision and control of the person with disabilities. Exception: When boarding an owner and service animal independently due to unusual circumstances such as the service animal not being able to use the stairs, the animal may be off the lead. In this circumstance, the animal should board first on the lift, then the customer. As soon as boarding is completed, the customer must replace the lead. When exiting, the customer deboards first, then the animal.

A service animal is any guide dog, signal dog or other animal individually trained to work or perform tasks for an individual with a disability, including, but not limited to, guiding individuals with impaired vision, alerting individuals with impaired hearing to sounds, providing minimal protection or rescue work, pulling a wheelchair or fetching dropped items.

While riding, the animal must sit or stand on the floor of the vehicle and may not block the aisle.

If an animal misbehaves, the customer will be asked to remove the animal from the vehicle. If there are multiple occurrences of misbehavior, the animal's riding privileges may be revoked. Examples of misbehavior include, but are not limited to, attacking customers, District employees or other service animals, or unprovoked growling.

Volunteers from the 4 H Club who raise puppies in training for Guide Dogs for the Blind may board SamTrans buses and Caltrain with these puppies, provided the trainer shows the identification card for the puppy. These puppies wear special coats provided by the 4 H Club to help bus operators and train conductors identify them as puppies in training.

Redi Wheels customers are required to notify the reservationist when they book their ride that a service animal will be accompanying them.