Simon Cowell and GF Lauren Silverman Living it up in Barbados

Simon Cowell's one major requirement for vacationing with him ... sunglasses, apparently.

Simon and his gorgeous GF Lauren Silverman hit up Barbados for the holidays. They were joined by family ... shown here as they arrive back to their Sandy Lane Villa. The warm weather and picturesque views were nice and all ... but nothing like a little monkey around to really get the party started.

Not sure how but sure seems like the monkey missed the memo -- grab yo shades, lil dude!!!