Kate Middleton and Prince William are hanging out in the Solomon Islands today -- this, as the Palace vows to get an injunction against an Italian mag, that's threatening to publish more than 200 topless pics of the Princess.

The Italian mag plans to unveil the photos in a 26-page spread Monday. But the Prince's legal team is on an International hunt to stop the dissemination of the photos ... showing Kate and William sunbathing on a balcony in a remote area of France.