Biển kéo dài {{convert|490|miles|sp=us}} từ bắc đến nam và {{convert|375|miles|sp=us}} từ đông sang tây. Các con sóng có thể trải dài {{convert|25|km|sp=us}} đến {{convert|35|km|sp=us}}.<ref name="INTERNAL WAVES IN THE SULU SEA">{{cite web|last1=Earth|first1=NASA's Visible|title=Internal waves in the Sulu Sea, between Malaysia and the Philippines|url=https://visibleearth.nasa.gov/view.php?id=70670|website=visibleearth.nasa.gov|access-date=23 April 2018|language=en|date=11 August 2009|archive-url=https://web.archive.org/web/20160316140203/https://visibleearth.nasa.gov/view.php?id=70670|archive-date=16 March 2016|url-status=live}}</ref> Biển có độ sâu {{convert|4400|m|sp=us}} nhưng ở đầu phía nam quần đảo Sulu đáy biển chỉ sâu {{convert|100|m|sp=us}}.<ref name="Encyclopedia Britannica: Sulu Sea"/>
{{quote|''On the Northwest.'' From Tanjong Sempang Mangayau, the North point of [[Borneo]], along the Eastern limit of [[South China Sea]] to Cape Calavite, the Northwest point of [[Mindoro]].
''On the Northeast.'' The Southwest coast of Mindoro to Buruncan Point, its Southern extreme, thence a line through Semirara and Caluya Islands to Nasog Point ({{coord|11|53|N|121|53|E|display=inline}}) the Northwestern extreme of [[Panay]], along the West and Southeast coast of that island to Tagubanhan Island ({{coord|11|08|N|123|07|E|display=inline}}), thence a line to the Northern extreme of [[Negros Island|Negros]] and down the West coast to Siaton Point, its Southern extreme, thence across to Tagolo Point ({{coord|8|44|N|123|22|E|display=inline}}), [[Mindanao]].
''On the Southeast.'' From Tagolo Point, down the West coast of Mindanao to the Southwest extremity thence to the North coast of [[Basilan (island)|Basilan Island]] ({{coord|6|45|N|122|04|E|display=inline}}), through this island to its Southern extremity, thence a line to Bitinan Island ({{coord|6|04|N|121|27|E|display=inline}}) off the Eastern end of [[Jolo|Jolo Island]], through Jolo to a point in long. 121°04'E on its South coast, thence through [[Tapul, Sulu|Tapul]] and [[Lugus, Sulu|Lugus]] Islands and along the North coast of [[Tawi-Tawi|Tawi Tawi Island]] to [[Bongao, Tawi-Tawi|Bongao Island]] off its Western end ({{coord|5|01|N|119|45|E|display=inline}}), and from thence to Tanjong Labian,<ref name="Encyclopedia Britannica: Tawi-Tawi"/> the Northeastern extreme of Borneo.
''On the Southwest.'' The North coast of Borneo between Tanjong Labian and Tanjong Sempang Mangayau.}}
