Free public transport
In downtown Copenhagen you will especially notice the red and yellow A-buses. They run about every 3-7 minutes during peak hours and every 10 minutes before and after rush hour. Additionally, you will see blue and yellow S-buses, which have fewer stops and therefore are faster, N-buses, which are night buses, and regular yellow buses that run every 20 minutes. You get on the bus in front, where you also show your Copenhagen Card to the driver. Remember to press the stop button when you wish to get off the bus, and use the rear or middle exit. You can bring a pram on the bus, and one dog is also allowed. The dog rides for free, if it is in a bag. Otherwise you need to purchase a child ticket for it. Copenhagen also has a few harbour buses that sail across the harbour and a battery-powered bus 11, which runs in a circle around the city's main attractions.
Copenhagen’s metro runs from Vanløse on the outskirts of the city via Copenhagen city centre to the airport and Vestamager. It runs round the clock seven days a week, and there are only 2-4 minutes between trains during rush hours and 3-6 minutes outside rush hour and on weekends. At night there is 7-20 minutes between trains. You can bring your bike on the metro outside of rush hour. You just need a bike ticket. You may also bring a pram and one dog. The dog must be in a bag. Otherwise, it needs a child ticket.
S-trains, as the red trains in Copenhagen are called, run from 05:00 in the morning till 00:30 in the night. After Friday and Saturday, they also run during night. There are a lot of different lines, which are all named with a letter, for example, lines A, B, C and E. Most trains run every 10 minutes on weekdays. Evenings and weekends there can be up to 20 minutes between trains. All trains stop at the stations in city centre, including Nørreport, Vesterport, and Copenhagen Central Station. Outside the metropolitan area, you can take the regional trains to ex. Roskilde and Elsinore (Helsingør). Additionally, you can find the rural yellow trains, Lokalbanen, from Hillerød, which will take you around North Sealand. You can bring your pram, bike and dog in a bag for free on the S- trains. The dog must have a child ticket, if it is not in a bag, and in regional trains you need a bike ticket, if you bring your bike.
Copenhagen Card offers free public transportation in the entire Copenhagen Region - See map here