The MTA's dog-in-a-bag rule, explained
Why New Yorkers stuff full-size dogs into IKEA bags to legally ride the subway.
Ride the subway long enough and you will eventually see it: a full-grown dog, sometimes a genuinely large one, riding in a giant blue IKEA bag, a canvas tote, or a duffel with its head poking out the top. It looks like a joke, but it is actually a New Yorker following the letter of an actual rule. The animal just happens to be too big for anything that looks like a normal pet carrier.
The rule behind it is real, on the books, and older than most of the memes it has produced. If you are the kind of transit nerd who already plays our NYC subway guessing game or pokes around the line and station explorer, this is one of those small pieces of system trivia worth knowing the next time a bag with legs gets on at your stop.
The actual regulation
The requirement sits in the New York City Transit Authority's rules of conduct, codified as 21 NYCRR § 1050.9. The relevant line says no person may bring any animal on or into a conveyance or facility "unless enclosed in a container and carried in a manner which would not annoy other passengers." The same section carves out an exception for law enforcement working dogs and for service animals and animals in service-animal training, which are allowed to ride harnessed or leashed instead of bagged.
Notice what the rule does not say. There is no weight limit, no breed list, and no specification of what counts as a container. It just has to fully enclose the animal. That silence is exactly the loophole that produced the whole bag culture: a duffel, a tote, or a shopping bag with the bottom cut out for legs technically satisfies "enclosed" just as well as a proper pet carrier does.
Why the MTA bothers with this at all
The rule is not really about dogs specifically. It sits inside a broader chapter on conduct and safety in shared transit space, next to rules about eating, spitting, and blocking doors, and it exists for the same basic reason those do: a crowded subway car is a small, shared, enclosed space, and one passenger's animal loose on the seats or floor becomes every other passenger's problem, whether that is shedding, sanitation, a bite risk, or simply a dog deciding it does not like someone's shoes. Requiring the animal to be contained keeps that risk off other riders rather than banning pets outright.
It is also, in practice, a rule almost nobody notices being followed correctly. A cat in a soft-sided carrier or a small dog zipped into a sling bag rides the system every day without anyone giving it a second look. The rule only becomes visible, and internet-famous, at the size extreme it was never really written for.
Enter the oversized tote
The workaround has been documented for years now. Time covered the trend of owners loading full-size dogs into IKEA shopping bags, canvas totes, suitcases, and hiking backpacks, sometimes cutting leg holes in the bottom so the dog can still stand while technically staying "enclosed." The look is somewhere between an optical illusion and a magic trick: a 50-plus-pound dog appears to be folded into a bag meant for flat-pack furniture, standing patiently on the platform like nothing is unusual.
It is a very New York solution to a very New York problem: a rule that is real, a fine that is real, and an entire dog that technically does not fit inside what most people would call a bag. Rather than fight the rule, owners just found the largest bag-shaped object they could carry.
How strictly is this actually policed
Not very, and it has gotten looser over time. Gothamist reported that enforcement has fallen off sharply: the NYPD issued 55 violations for unauthorized animals in the first half of 2019 but only 10 for all of 2023, even as an MTA board member acknowledged seeing more dogs on trains and fewer of them actually in bags. Riders quoted in the piece described bringing large, unbagged dogs aboard regularly with no consequence at all.
In other words, the rule exists, the IKEA-bag workaround is a genuine good-faith attempt to follow it, and plenty of dogs these days are not bothering with a bag in the first place. Nobody is likely to get thrown off a train for it, but if a conductor or officer does care, the container rule is exactly what they will cite.
Questions people actually ask
Is there really a law that a dog has to be in a bag on the NYC subway?
Yes. It is 21 NYCRR § 1050.9, part of the Transit Authority's rules of conduct, and it requires any animal to be enclosed in a container in a way that does not annoy other passengers.
Does the container have to be a real pet carrier?
No. The rule only requires the animal to be enclosed, not that the container be purpose-built for pets, which is exactly why IKEA bags, totes, and duffels satisfy it in practice.
Is there a size or weight limit for dogs on the subway?
No. The regulation does not mention weight or breed at all, so a large dog is allowed on the same terms as a small one as long as it is fully enclosed.
Are service dogs exempt from the bag rule?
Yes. Service animals and dogs in service-animal training are exempt and may ride harnessed or leashed instead of bagged, per the same section of the rules of conduct.
Do people actually get fined for having a dog loose on the train?
Rarely these days. Reporting from Gothamist found enforcement has dropped sharply over the past several years, though the rule technically remains in force.