You can also use the more informal "bienvenidos" (plural) or "bienvenidas" (plural feminine).
Here's how to use it:
* "Bienvenido a Colombia!" (Welcome to Colombia!)
* "Bienvenida a mi casa." (Welcome to my house.)
* "Bienvenidos a la fiesta." (Welcome to the party.)
* "Bienvenidas a la clase." (Welcome to the class.)