Rhynchoconger trewavasae is an eel in the family Congridae (conger/garden eels). It was described by Adam Ben-Tuvia in 1993. It is a marine, deep water-dwelling eel which is known from the western Indian Ocean, including the Gulf of Aqaba and possibly the Gulf of Suez. A single specimen was recorded in the Mediterranean Sea from Israel in 1993. It dwells at a depth range of , and swims in a zigzag motion near the bottom. Males can reach a maximum total length of , but more commonly reach a TL of .
The species epithet "trewavasae" was given in honour of British ichthyologist Ethelwynn Trewavas.
R. trewavasae is sometimes caught in traps and trammel nets.