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

Yes

The spelling, meaning, and grammatical usage of "Tailândia" are identical in both Brazilian and European Portuguese. The only difference is in pronunciation. In Brazilian Portuguese, the vowels tend to be more open and the rhythm is more melodic (syllable-timed). In European Portuguese, there is significant vowel reduction, meaning unstressed vowels are pronounced much more softly or are nearly swallowed, resulting in a more "clipped" or consonant-heavy sound.

Brazilian Portuguese Examples

1. Eu sempre sonhei em conhecer a Tailândia. (I have always dreamed of visiting Thailand.)
2. A comida da Tailândia é muito gostosa. (Thai food is very tasty.)
3. Eu fui para a Tailândia nas minhas férias. (I went to Thailand on my vacation.)
4. As praias da Tailândia são maravilhosas. (The beaches in Thailand are wonderful.)
5. Você já comprou a passagem para a Tailândia? (Have you already bought the ticket to Thailand?)

European Portuguese Examples

1. Sempre quis visitar a Tailândia. (I have always wanted to visit Thailand.)
2. A gastronomia da Tailândia é deliciosa. (Thai gastronomy is delicious.)
3. Fui à Tailândia durante as férias. (I went to Thailand during the holidays.)
4. As praias da Tailândia são de sonho. (The beaches in Thailand are a dream.)
5. Já compraste o bilhete para a Tailândia? (Have you already bought the ticket to Thailand?)