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

No.

While the spelling, grammar, and literal meaning of "cabelos" are identical in both varieties, there is a difference in typical usage and pronunciation.

In Brazilian Portuguese, it is much more common to use the plural "cabelos" to refer to the entire mass of hair on someone's head, particularly in beauty advertisements, hair care contexts, or descriptive writing. In Continental Portuguese, the singular "cabelo" is the standard way to refer to the mass of hair on one's head; the plural "cabelos" is more strictly reserved for referring to individual strands or specific locks of hair. Additionally, the pronunciation differs: Brazilian Portuguese features more open, distinct vowels, whereas Continental Portuguese features significant vowel reduction, making the unstressed "e" in "cabelos" almost silent.

Brazilian Portuguese Examples

1. Ela tem cabelos muito cacheados. (She has very curly hair.)
2. Encontrei alguns cabelos brancos no espelho. (I found some white hairs in the mirror.)
3. Os cabelos dela são bem longos. (Her hair is quite long.)
4. Ele tem cabelos pretos e lisos. (He has black, straight hair.)
5. Você precisa cuidar dos seus cabelos. (You need to take care of your hair.)

Continental Portuguese Examples

1. Ela tem o cabelo muito encaracolado. (She has very curly hair.)
2. Encontrei alguns cabelos brancos no espelho. (I found some white hairs in the mirror.)
3. O cabelo dela é bem comprido. (Her hair is quite long.)
4. Ele tem o cabelo preto e liso. (He has black, straight hair.)
5. Tu precisas de cuidar do teu cabelo. (You need to take care of your hair.)