The Montreal public transit system is pretty sweet. For $3 you can jump on any bus (heads up they don't give change) or metro (they do) and get to most places on the island. Most of the core metro stops were originally built right before Expo 67 - in other words, a bunch of urban planners and artists spent a bunch of money to make beautiful transit that would help showcase Montreal to the world. Each original station featured a different Quebecois artist, so sometimes you'll pop out of the metro below giant stained glass, or come up the stairs to face an enormous sculpted tree. The Mtl subway system is the most used system in Canada, the city has been coordinating forms of public transit since 1861 and you do get the feeling that, though not perfect, it's something Mtl takes seriously and tries to do right. \n\nThe subway and buses are very clean and even kind of chic compared to Toronto or NYC's, and the system is simple to navigate: eg unlike other city's subways you won't have different trains running the same track, stopping at the exact same spot requiring you to read a sign on the train itself to make sure you've got the right one. In Montreal if you stand on the right platform, you're getting on the right train. \n\nThe monthly pass is called the Opus card, it costs about $70 a month for unlimited rides if you're an adult, but you can also just buy 10 or 20 rides at a time on your Opus card and they won't expire at the end of the month - a sweet cheap option for a commuter like me who doesn't need to use transit every day. When you swipe your Opus card at the metro turnstile it shows you how many rides you have left so you know when to refill. It doesn't have a photo on it, but you can register your Opus card number at Berri, Jean Talon, Snowdon, or Lionel to protect you in case of loss or theft. \n\nIf you're a visitor you can check out the 1 day or 1 week rates, but these have set start and end days and times that I find confusing personally. When folks visit me we just buy the $20 pack of 10 tickets - these can be used on the bus or metro, they include transfers, and they don't expire for a year (or more?) so whatever my guests don't use doesn't go to waste. \n\nWhen using these tickets on the metro just slide the ticket into the slot as indicated, wait for it to pop back up, then remove it and push through the turnstile.\n\nThe metro stops downtown - eg McGill, Peel - connect to the underground malls, so you can shop and wander indoors for miles in the winter. Calling this an underground city is overselling it, but for mall basements connected by tunnels and metros it's arright.\n\nThe metros generally stop running around 1am, except during nuit blanche when they run all night. There are useful night buses that run most of the major arteries, and the lineup for these at 3am is jovial, boozy and ridiculous (the one to Montreal West and the West Island leaves from Atwater). \n\nIn general I've had great experiences with the drivers and staff at the metros and on the buses - special shoutout to the singing driver who is beloved on every route he drives. The staff are mostly but not always bilingual, but anyway all the automated tellers have an English option. There is confusion every time they change the system, but that's to be expected and doesn't happen too often. There was a brief period when STM bus drivers all seemed like jerks because they would drive away from passengers trying to cross the street or running up at the last second to catch the bus, but someone seems to have changed their mind about this jerkiness being a good idea and now they act like kind-hearted humans again, waiting that extra second for little old ladies trying to catch the bus, and things are much better.