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

No

While the spelling, grammar, and core definition of "viaja" (the third-person singular present of viajar) are identical in both variants, there are two key differences:

• Pronunciation: In Brazilian Portuguese, the vowels are typically more open and clearly articulated, and the rhythm is "syllable-timed." In Continental Portuguese, unstressed vowels (like the final 'a') are often "reduced" or nearly swallowed, and the rhythm is "stress-timed."
• Typical Usage: In Brazil, "viaja" is frequently used as slang to mean "to be out of touch," "to daydream," or "to be tripping/hallucinating" (e.g., Ele viaja muito). In Portugal, the word is almost exclusively used in its literal sense of physical travel.

Brazilian Portuguese Examples

1. Ela viaja sempre de avião. (She always travels by plane.)
2. Ele viaja de ônibus todos os dias. (He travels by bus every day.)
3. Ele viaja demais, nem sempre é realista! (He's tripping/daydreaming too much, he isn't always realistic!)
4. Ele viaja sempre com o seu celular. (He always travels with his cell phone.)
5. Ela viaja nas férias de janeiro. (She travels during the January holidays.)

Continental Portuguese Examples

1. Ela viaja sempre de avião. (She always travels by plane.)
2. Ele viaja de autocarro todos os dias. (He travels by bus every day.)
3. Ele viaja muito a trabalho. (He travels a lot for work.)
4. Ele viaja sempre com o seu telemóvel. (He always travels with his mobile phone.)
5. Ela viaja nas férias de agosto. (She travels during the August holidays.)