Cubemaps artifact

Hello, I am creating a cube map texture and I have applied it to a cube. It works but it has an artifact where the texture joins.

This is the original texture (from Paul Bourke website)


I am quite sure I am not the first one who has this problem. Is there a standard way to go? What I think to do is to increase the text coord in that sides where the texture “closes”, so that the image will cover the empty space. Any other suggestion?

This is the code that I am using atm

usually glEnable(GL_TEXTURE_CUBE_MAP_SEAMLESS) solves this issues