Workers at three separate rail companies will walk out over a long-running dispute about staffing on the network, the RMT union has announced.
Southern Railway and Arriva Rail North will see staff strike on Friday 1 September and Monday 4 September, while Merseyrail workers will walk out on 1, 3 and 4 September.
Busy services including the Gatwick Express, the London to Brighton line and journeys across much of northern England could be affected by the strikes, which take place just as children will be returning to school.
The action relates to long-planned changes which would see drivers given responsibility over opening and closing the doors of train carriages, with some services staffed only by a driver as guard roles are changed to 'onboard supervisors'.
Members of the RMT union have been striking for a year to show their opposition to the plans, but rail bosses have said they intend to go ahead with the changes.
There have already been strikes held on all three lines this year in relation to the issue.
"RMT is bitterly disappointed that Southern Rail have rejected our call for round-table discussions involving all parties with an interest in resolving this dispute," said RMT general secretary Mick Cash.
"The failure to get those talks moving following our face-to-face meeting with Transport Secretary Chris Grayling has left us no option but to call further action."
Union bosses had held a meeting with the Arriva Rail North on Friday but accused the company of "intransigence" over the issue.
"The responsibility for the inevitable disruption lies wholly with the company," said Mr Cash.
In response, Northern boss Alan Chaplin said there was "no doubt" the plans to strike would "damage the region's economy, significantly disrupt our customers' lives, and impact local businesses".
"Our offers to discuss every detail on the future responsibilities and training for on-board colleagues have been rejected by RMT," he said.
"We want to make changes to the on-board colleague role to make it fit for the future, better supporting customers on trains and at stations."
Jan Chaudhry-van der Velde, Merseyrail's managing director, said: "The RMT say this dispute is about safety but a recent industry report states that there is no additional risk for passengers boarding and alighting driver-only trains."
Southern Rail have yet to comment on the announcement.