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

Yes

The word "ilhas" is identical in meaning, spelling, and grammar in both Brazilian and European Portuguese. The only difference is in pronunciation. In Brazilian Portuguese, vowels are generally more open and clearly articulated. In European Portuguese, unstressed vowels tend to be "reduced" or "swallowed," which can make the word sound shorter or more clipped to a Brazilian ear.

Brazilian Portuguese Examples

1. Eu adoro viajar para ilhas paradisíacas. (I love traveling to paradisical islands.)
2. As ilhas do Caribe são muito famosas. (The Caribbean islands are very famous.)
3. Nós vimos várias ilhas de longe. (We saw several islands from afar.)
4. As ilhas de Fernando de Noronha são incríveis. (The islands of Fernando de Noronha are incredible.)
5. Você conhece as ilhas da Grécia? (Do you know the islands of Greece?)

European Portuguese Examples

1. Gostava de viajar para ilhas paradisíacas. (I would like to travel to paradisical islands.)
2. As ilhas do Caraibes são muito famosas. (The Caribbean islands are very famous.)
3. Nós vimos várias ilhas à distância. (We saw several islands from a distance.)
4. As ilhas dos Açores são incríveis. (The Azores islands are incredible.)
5. Tu conheces as ilhas da Grécia? (Do you know the islands of Greece?)