Reigning champions Worcestershire will start their 2019 Vitality T20 Blast campaign with an away clash against Nottinghamshire on July 18.
As well as the North Division contest at Trent Bridge, the opening day of the tournament also features two South Division fixtures - Middlesex against Essex at Lord's and Glamorgan hosting Somerset, who reached the 2018 semi-finals.
The quarter-finals will be on consecutive days from September 4-7 and the semis and final are scheduled to take place on September 21 at Edgbaston.
Sussex, the 2018 runners-up, start at Hampshire on July 19, when Worcestershire host Birmingham Bears.
That Friday also sees Lancashire, the other side beaten in the last four last time, take on three-time winners Leicestershire at Grace Road.
Lancashire face Roses rivals Yorkshire at Headingley on July 25 and Old Trafford on August 9.
The last six editions have been won by North Division sides, and Sussex this year became the first South Division outfit to make the final since 2013.
Victory over them by five wickets in September's final saw Worcestershire secure the trophy for the first time.
The 2019 fixtures have also been announced for the six-team Kia Super League.
Defending champions Surrey Stars play Yorkshire Diamonds at Headingley on the opening day, August 6.
Loughborough Lightning, who they beat in the 2018 final, host Western Storm and Lancashire Thunder face Southern Vipers.
The semi-finals and final will be held on September 1 at Hove.