This is a genuine feature of the east coast, not an exaggeration, and it is worth understanding before you book rather than being caught off guard.

The east coast, including Paje, Jambiani and Bwejuu, has a very wide tidal range. At low tide, the water can retreat several hundred metres from the shore, exposing sandbars and shallow lagoon areas rather than the deep blue water you might be picturing. This happens twice daily, so there are windows within each day where the beach looks completely different depending on the tide.

Seaweed farming is a real local industry along parts of this coast, with visible rows of seaweed lines in the shallows in some areas, most noticeably around Paje and Jambiani. It is not everywhere and not constant, but it is a genuine part of the local economy and landscape, not litter or pollution, and it is worth seeing it that way rather than as a flaw.

None of this makes swimming impossible. At high tide, the east coast has proper swimmable water, and many resorts have pools as an alternative during low tide windows regardless. Snorkelling and diving trips out to reef areas, rather than directly off the beach, avoid the tidal and seaweed issue entirely and are genuinely excellent along this coast.

If consistently deep, swimmable water right off the beach at any time of day is your top priority, the northern coast around Nungwi has a much smaller tidal range and is the better choice. If you want a quieter, more traditional coastal atmosphere with excellent kitesurfing and do not mind planning swims around the tide chart, the east coast remains a wonderful choice.