The honest advice is to aim for a healthy, even glow that you build gently and safely, and to treat the equatorial sun with real respect. Seychelles sits four degrees off the equator, where the UV index regularly reaches eleven or above, the very top of the scale, all year round, so the sun is far stronger than at home and can burn in less time than you expect. A sunburn on your wedding day is uncomfortable and photographs harshly, and awkward tan lines are surprisingly hard to hide in a beach dress, so a little care in the days before pays off in every picture.
Build a glow, do not risk a burn
If you want colour for the day, build it gradually in the weeks before your trip rather than trying to bake it on in the first two days on the island. A gentle, even base tan or a good gradual self-tan looks far better on camera than a fresh burn, and it will not peel. Once you arrive, be especially careful in the first days, because the strongest sun does its damage before you feel it. The goal is to look well, not to look cooked.
The spray-tan trap
A word of honest warning about spray tans. A fresh spray tan applied just before a tropical wedding is a real risk, because heat, humidity and even a little sweat or sea can cause it to streak, transfer onto a white dress, or go patchy. If you love a spray tan, do it well before you travel and let it settle, or choose a light gradual product you can control. The last thing you want is bronzer on the inside of your gown in the golden-hour shots.
Protect your skin, and the reef
Wear a high-protection sunscreen every day of the trip, including the wedding morning, and reapply it, because protecting your skin is what keeps you glowing rather than red. Make it a non-nano mineral, reef-safe one, using zinc or titanium, which Seychelles asks visitors to use so the sun cream does not harm the coral, and a light rash guard in the water helps on both counts. Do not trust the sea breeze either, it hides the burn while the sun stays just as strong. Mind the tan lines, since straps and swimwear leave marks that show in a strapless or open-back dress, and keep your shoulders covered in the fierce midday hours in the days before, so your skin is calm and even when it matters.