The drive to Sandwich Harbour is right along the edge of the dunes and water south of Walvis Bay so the dunes are bigger than the ones around Swakopmund. It was really windy so we didn't spend much time driving around in the dunes, I wish we had but oh well. Overall it cost us $150 USD each for the day. If it cost $100 I would recommend it without hesitation but it is expensive. There are lots of tours that do half day trips to Sandwich Bay, I think that would feel rushed, it's a good 90 minute drive from Swakopmund. If I had to do it again I would skip the day to Sandwich Harbour and splurge on a flight over the dunes.. or do the living desert tour with tommy's, you get to spend more time driving in the dunes and see a lot more critters, and it costs half as much.
That said, Turnstone is very professional, and it was a full day, almost 10 hours door to door. Our guide was funny, friendly, and very outgoing. Lunch was delicious (lasagna) and the apple crumble for desert is the best I've ever tasted in my entire life. About ten times better than the world famous apple crumble everyone talks about in Solitaire. So if you have the time and money, go for it. But if you're on a budget financially or time wise.. I would prioritize kayaking with seals, quad biking in the desert (everyone should do this), and tommy's living desert tour. If you can afford it, we heard (from other travellers) that the desert flights are incredible if you have a window seat :)
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