Whilst birding the Uqair area on the edge of the Arabian Gulf with Phil Roberts in late November, I came across a large group of Black-necked Grebes. Phil had is scope with him and after confirming their identification and number totaling over one hundred birds we scanned the entire visible bay. We found several more groups and smaller numbers scattered around and estimated the total to be well over 500 birds. The birds were very active feeding and diving so an accurate count was impossible. They were also mainly well offshore and did not approach the coast itself whilst we were present. Large numbers of fifty or more have been recorded in the Half Moon Bay area 50 kilometres north of this record, but no numbers as large as this have been noted. Our previous largest group was 192 birds at an inland lake at Dawmat Al Jandal, Jouf province in the northwest of the Kingdom in January 2019. This is the largest ever gathering of the species in Saudi Arabia and they may stay throughout the winter.