Buy Card for Subway Beijing

The card can be bought but you need to upgrade it to use and top up which needs a valid ID card to finish, and most service centers only accept China ID Card. For foreigners who want to get one with passports, they need to go to the service center in Dongzhimen to get one and upgrade it.

You have probably mistaken one way ticket with Beijing Yikatong transportation card. Ticket vending machine in Beijing Subway often require id number to buy one way ticket, which is a bad habit left over from COVID era.

In reality in Beijing, there seem to be a lot of stations still requiring ID verification to buy a one way ticket or to buy or charge transportation card. But also, there are enough places that they abolished this ID verification thing. It us better to go to busy place for better chance. Or you can make day trip to Tianjin in earlier stage of your trip to Beijing to buy a working transportation card.