If you are congratulating a relative, it is better to choose warm, heartfelt phrases. In Spanish-speaking culture, birthday greetings often sound emotional: people wish health, joy, love, well-being, and say how important the person is to them.
The simplest option:
¡Feliz cumpleaños!
Happy Birthday!
This phrase works in almost any situation. You can write it in a message, say it in person, add it to a card, or use it in a story.
For a mother, father, grandmother, grandfather, brother, or sister, you can say it more warmly:
¡Feliz cumpleaños, mamá! Te quiero muchísimo.
Happy Birthday, Mom! I love you very much.
Papá, te deseo un día maravilloso. ¡Feliz cumpleaños!
Dad, I wish you a wonderful day. Happy Birthday!
Que tengas un año lleno de salud, amor y alegría.
May you have a year full of health, love, and joy.
Gracias por estar siempre a mi lado. ¡Feliz cumpleaños!
Thank you for always being by my side. Happy Birthday!
If you want to write a more beautiful birthday message for a relative, you can use this version:
Hoy es un día muy especial porque celebramos tu vida. Te deseo mucha salud, alegría, amor y momentos bonitos junto a las personas que te quieren. ¡Feliz cumpleaños!
Today is a very special day because we are celebrating your life. I wish you lots of health, joy, love, and beautiful moments with the people who love you. Happy Birthday!
In Spanish, the word querido / querida is often used — dear:
Querida abuela, feliz cumpleaños. Te deseo mucha salud y felicidad.
Dear Grandma, Happy Birthday. I wish you lots of health and happiness.
Querido hermano, que todos tus sueños se hagan realidad.
Dear brother, may all your dreams come true.