Having finished last season with pole in the New York finale, Sims had also been fastest on Friday for the first race of the double-header weekend in Saudi Arabia. It's the first time that any driver in the history of the all-electric championship has achieved three poles in a row.
Sims survived a wild four-wheel drift out of turn 17 to set a pole position time of 1:11.476s, 0.220s quicker than former champion Sebastian Buemi.
Lucas di Grassi will start today's race alongside Mitch Evans on the second row, while an early lock-up on his superpole lap meant that Jérôme d'Ambrosio ended up only fifth fastest.
Techeetah's António Félix da Costa had been quickest in both the earlier morning free practice sessions and in his qualifying group, but suffered two big slides during his final time trial and was slowest of the superpole contenders in sixth.
The drivers had gone into qualifying still concerned about the dusty and sandy conditions on the desert track, meaning they tried to hold back before starting their flying laps in the hope that their rivals would 'sweep the road' first.
The first group was at particular disadvantage, Envision Racing's Sam Bird followed up his first-round win on Friday by topping the group with a time of 1:12.007s ahead of Porsche's Andre Lotterer and Mercedes' Stoffel Vandoorne.
Sam Bird wins opening 2019-20 race in Saudi Arabia
However, speeds immediately cranked up in round two with Mahindra's Jérôme d'Ambrosio fastest of anyone so far with a time of 1:11.835s despite glancing the wall at the exit of the final corner.
Friday polesitter Sims was only 0.023s slower than d'Ambrosio, with Mitch Evans third fastest for Jaguar. All three were quicker than Bird's time.
Techeetah's António Félix da Costa had topped both the earlier two free practice sessions in the morning. He confirmed that pace by topping the fourth group and going four tenths quicker than d'Ambrosio.
Audi's Lucas Di Grassi was second quickest in the group and good enough for fourth overall, meaning that only Bird now remained in potential superpole contention having been pushed down to sixth.
Bird was finally eliminated by Nissan e.dams' Sebastian Buemi topping the third group with a time of 1:11.774s to go second overall. Reigning champion Jean-Eric Vergne was second quickest in the group but not fast enough to make it into the top six. He'll start the race from 11th.
Also among those missing out on going for pole position were Venturi's Edoardo Mortara, BMW's Max Guenther and Friday podium winners Lotterer and Vandoorne. They will be starting the race from eighth, ninth, tenths and 12th respectively.
Virgin's Robin Frijns will start from 13th with Pascal Wehrlein lining up in 14th for Mahindra, Oliver Rowland in 17th for Nissan e.dams, and Nyck de Vries relegated to the back of the grid in the second Mercedes.