Data at a site

https://forecast.metoceanapi.com/ocean/gfs/site?times=R56/20170901T150000Z/PT3H&lon=161.396&lat=-37.464&units=nautical

Data along a route

https://forecast.metoceanapi.com/ocean/gfs/route?times=R12/20170901T150000Z/PT3H &lons=-34.120,-31.077,-27.305,-26.270,-22.680,-21.220,-18.847,-17.752,-14.953,-13.188,-10.572,-7.773&lats=45.937,46.526,47.522,48.619,50.397,52.148,54.439,55.071,55.658,56.339,56.641,56.641&units=nautical

Note that it is important to make sure that there are the same number of longitudes, latitudes and times in a route request.