Is the word cartões the same in Brazilian and European Portuguese?

Yes

The spelling, meaning, and grammatical function of the word "cartões" are identical in both Brazilian and Continental Portuguese. The only difference lies in pronunciation. In Brazilian Portuguese, the final syllable "-ões" is pronounced with a clear, distinct "is" sound (similar to kahr-TOW-ees). In Continental Portuguese, the final syllable is much more reduced and "closed," often sounding more like a short, palatalized "sh" or a very swallowed "y" (similar to kahr-TÕSH).

Brazilian Portuguese Examples

1. Eu perdi meus cartões de crédito. (I lost my credit cards.)
2. Você aceita cartões de débito aqui? (Do you accept debit cards here?)
3. Eu gosto de colecionar cartões-postais. (I like to collect postcards.)
4. Onde estão meus cartões de visita? (Where are my business cards?)
5. Os cartões de embarque já foram impressos. (The boarding passes have already been printed.)

Continental Portuguese Examples

1. Eu perdi os meus cartões de crédito. (I lost my credit cards.)
2. Aceitam cartões de débito aqui? (Do you accept debit cards here?)
3. Eu gosto de colecionar postais. (I like to collect postcards.)
4. Onde estão os meus cartões de visita? (Where are my business cards?)
5. Os bilhetes de embarque já foram impressos. (The boarding passes have already been printed.)