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

Yes.

The word "praias" is identical in meaning, spelling, and grammar in both Brazilian and Continental Portuguese. The only difference is the pronunciation of the final "s." In Brazilian Portuguese, the "s" is typically pronounced as a voiceless alveolar fricative [s], similar to the English "s" in "sun." In Continental Portuguese, the "s" at the end of a word is typically pronounced as a voiceless postalveolar fricative [ʃ], similar to the English "sh" in "shoe."

Brazilian Portuguese Examples

1. As praias do Nordeste são maravilhosas. (The beaches of the Northeast are wonderful.)
2. Eu adoro passar o dia nas praias. (I love spending the day at the beaches.)
3. Quais são as melhores praias do Rio? (What are the best beaches in Rio?)
4. As praias daqui ficam muito cheias no verão. (The beaches here get very crowded in the summer.)
5. Quero conhecer novas praias este ano. (I want to visit new beaches this year.)

Continental Portuguese Examples

1. As praias do Algarve são deslumbrantes. (The beaches of the Algarve are stunning.)
2. Gosto de ir a praias mais calmas. (I like going to calmer beaches.)
3. As praias da zona são muito bonitas. (The beaches in the area are very beautiful.)
4. Fomos a várias praias durante as férias. (We went to several beaches during the holidays.)
5. Estas praias são ideais para surfar. (These beaches are ideal for surfing.)