I had a day to spare between flights and like sand dunes so made a quick visit here in Sept 2024. This is an easy day trip from Nadi on public transport even on a Sunday when I went since there are still regular buses traveling along the southern route between Suva and Lautoka. The ride is a little more than an hour from Nadi and there is no official bus stop at the entrance to the dunes but the driver was able to pull over at a reasonably close distance so I could walk back along the road. On the way back to Nadi be prepared to walk a few hot km back to the Sigatoka bus station or get lucky as I did and get a lift there from a friendly local.
Sigatoka Sand Dunes are Fiji's first national park and a visitor here would be forgiven for never realizing that it wants to be a cultural site. In the entrance room/museum where you buy your ticket is a small display of reconstructed pottery (by my old university!) and brief explanation about the early inhabitants but most of the focus is on the natural aspects of the dune environment itself.
There are 2 loop trails starting from the same spot and I'd recommend the 2-hour loop over the 1-hour one to be able to be able to visit the larger dunes at the eastern end of the park and have a bit more time along the shore. The walk itself, other than the heat, is quite pleasant and the majority is very green; grassy at the beginning and through mahogany forest with bats at the end.
The archaeological dig site is shown on the map at the entrance and when I asked about it the park staff just shrugged his shoulders and said the dig team hasn't been back for years and "people go there". I took this as permission to look around and ended up walking all the way to the mouth of the river searching for the excavations but found nothing other than the occasional pottery shard and some litter. It is either very well hidden or has been swallowed up by the sand again and after getting too close to overheating I gave up and continued back along the trail.
I enjoyed my visit and understand the archaeological significance of the location but for a nomination based on that it feels like there is nothing left to preserve or display and would ultimately be rather pointless.