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

Yes

The word "viajam" is identical in spelling, meaning, and grammatical function in both Brazilian and Continental Portuguese. The only difference lies in pronunciation. In Brazilian Portuguese, the vowels are generally more open and the rhythm of the word is more syllabic. In Continental Portuguese, unstressed vowels—specifically the "a" in the final syllable "-am"—tend to be much more closed or even reduced to a nearly silent sound, making the word sound shorter and more "clipped" to an untrained ear.

Brazilian Portuguese Examples

1. Eles viajam muito durante as férias. (They travel a lot during the holidays.)
2. Meus amigos viajam de ônibus para o Rio. (My friends travel by bus to Rio.)
3. Vocês viajam sempre com malas grandes? (Do you all always travel with large suitcases?)
4. Elas viajam para o exterior todo ano. (They travel abroad every year.)
5. Os turistas viajam muito no verão. (The tourists travel a lot in the summer.)

Continental Portuguese Examples

1. Eles viajam muito durante as férias. (They travel a lot during the holidays.)
2. Os meus amigos viajam de autocarro para o Porto. (My friends travel by bus to Porto.)
3. Eles viajam sempre com malas grandes? (Do they always travel with large suitcases?)
4. Elas viajam para o estrangeiro todo o ano. (They travel abroad every year.)
5. Os turistas viajam muito no verão. (The tourists travel a lot in the summer.)