Katherine Brunt, Jenny Gunn, Danielle Hazell and Lauren Winfield are the Diamonds’ first recruits ahead of the T20 tournament that starts in July.
The competition features six teams, with Diamonds opening their campaign against Loughborough Lightning at Headingley on July 30.
Jo Kirk, Kia Super League general manager, said: “The key considerations when initially approaching the player allocation process were to ensure an even balance of talent across the six teams, alongside factoring in the local allegiances of the players as much as possible.
“Each of the teams will have a squad of 15 players, which will consist of a maximum of four centrally contracted England players, three overseas players, and a maximum of three England Women’s Academy players.
“The remainder of players will come from the England Women’s Development Programme and a comprehensive county talent identification process.
“By the end of this process, the ECB will have collaborated extensively with the six hosts to select 90 players from a talent pool of nearly 200 from this country and across the world.”
Katherine Brunt, the Diamonds’ pace bowler, said: “I’ve played my entire cricket career for Yorkshire CCC and I’m very proud that I’ll get to represent the Diamonds in this latest chapter of the development of women’s cricket in the county.
“It’s already looking to be a strong line-up, with Lauren leading the batting line-up, me and Jen filling those all-rounder spots, and Danni offering our spin option.
“I’m looking forward to seeing the balance of the squad when the overseas players are confirmed in the next few weeks.”