I was here with @Holly again in April of 2018, another Sargassum-free beach on beautiful Saint Lucia.
This time, the Grande St Lucian. Among the Sandals properties on the island, it's probably got not only the largest beach area but also the most beautiful views across the bay.
Better than that, there was no seaweed to be seen along the length of that amazing beach!
The resort does groom the sand somewhat, but I don't think there was much green stuff for them to pick up at the time.