The present invention relates to a method for protecting the skin against UV rays, using two cosmetic compositions for protecting against UV rays, the sun protection indices of which are different from each other, this method consisting in applying to the skin, before or during exposure to sunlight, a first composition having a certain sun protection index, and then in applying, during exposure to sunlight, onto the residual deposit of the first composition, the second cosmetic composition having a sun protection index lower than that of the first composition. This method advantageously makes it possible to not reapply the first composition, but to use a second product that is much more pleasant to use, while at the same time obtaining the level of protection afforded by the deposit of the initial first composition. The invention also relates to a sun protection kit comprising a first composition for protecting against UV rays having a sun protection index of greater than or equal to 30, and at least a second cosmetic composition for protecting against UV rays, having a sun protection index of less than or equal to 20, the two compositions being packaged separately.