A bloke must have his toys and a Yamaha Grizzly is my favourite. Bike-riding is poor man's flying. On the West Coast the bureaucrats haven't banned bikes from the beachs yet so most blokes have a bike and ride free for miles down the coastline.
As you head south from Okarito the first adventure is negotiating the narrow sand strip between the surging Tasman sea and the cliffs. This can only be done two hours either side of low tide. To make things more interesting the route is littered with boulders, aptly named by geologists as "eratics". What they do is cause you to pause just long enough to be lined-up by the next rogue wave. Woosh!!! Tangaroa, the Maori god of the sea, will poke out his tongue doing his utmost to suck you and your bike into the surf. On this coastline he is not known for taking prisoners.
The next bit of drama comes at the outlet of Three-mile Lagoon. In the 1870's, 21 poor gold miners drowned at this place. The outlet is usually blocked by a narrow sand bar making crossing a breeze. But if the lagoon is open then you must make a decision whether a ford is feasible or not, keeping in mind the 21 who misjudged the call! There is often "sinky-sand" in the ford just to make things interesting.
After a successful ford, the travel south is smooth along the sandy beach until the Five-mile Lagoon outlet is reached. This requires another life or death decision on whether to ford. Beyond is Five-mile beach a more remote and rougher stoney beach but the views are majestic. Mts. Cook, Aoraki, and Tasman, Horo-Koau, tower over the landscape.
Finally, the journey ends at the Waiho River, which is like reaching the beginning of another world. Unfortunately, as it is with life itself, the next world is beyond reach. The Waiho is definitely an ugly river, rarely fordable.
No alternative but to retrace the journey home. If you want more thrills there is a large steep-sided sandhill at Three-mile where you can rapidly attain your level of incompetence as a rider. Only centrifugal forces generated by speed keep you on the sandhill so it is a death or glory game.
Time for home before you run out of tide.