Short (2005) lists the most extensive sand coasts on each continent:
North America the southeast and Gulf coasts, both low-gradient passive margin coasts supplied by numerous rivers including the Mississippi, with the sand reworked onshore by a high-energy wave environment. However, coastal dunes are poorly developed. Also parts of the west coast exposed to high shelf sediment supply and winds to build dunes.
South America massive long-term sand supply to entire east coast, leading to an essentially sand barrier / dune coast from the Amazon south to Argentina. Long beach-barrier-dune systems for much of the coast.
Africa beach, barrier and dune systems ring most of the continent, with sand supplies by local rivers, including the Nile, Niger, and Orange, and on the most exposed coasts by shelf supply of quartz, and in the south also carbonate sands.
Eurasia sand dominates most exposed western (Europe-Mediterranean), southern (India), and eastern shores (Southeast Asia-China), with some substantial river systems and deltas and extensive sand barriers in South India and Sri Lanka.
Australia 50 % of passive margin coast consists of sand deposits, with low-energy beaches in the north through high-energy beaches and dune systems across the south. Supply from rivers and shelf in the north, and from shelf quartz in the southeast and carbonate in the south and west.