Strikes 'could shut 300 schools' in Essex
More than half of the 550 schools across Essex will be hit by strikes, according to unions.
The National Union of Teachers (NUT) in Essex said more than 300 schools to be closed or partially closed.
Southend Council said 37 out of its 55 schools would be disrupted.
The Public and Commercial Services Union (PCS), representing immigration officers and job centre staff, also expects Stansted Airport and Harwich International Port to be affected.
A spokesman for Stansted Airport said that due to the strike "arriving passengers may experience delays at passport control".
'Anger over pensions'
The strike is also likely to disrupt job centres in the county.
The unions are concerned at plans to change public sector pensions.
The four teaching unions involved are members of University College Union (UCU); the National Union of Teachers (NUT); the Association of Teachers and Lecturers (ATL) and National Association of Head Teachers (NAHT).
Jerry Glazier, general secretary of Essex NUT, said: "The message to the government is that teachers are angry at the way the government wants to treat their pension in the future.
"We can't see why the government wants to tax teachers."
Essex county councillor Stephen Castle, cabinet member for education, said: "It is extremely disappointing that children's education could suffer because of strikes forcing some schools to close.
"This unwarranted course of action is disruptive to parents and children's education. We are of course advising schools throughout this time."
Essex County Council said it had so far been notified of 26 closures but admitted the figure was likely to rise.
Southend Council has provided a list of schools which are being closed or partially closed on its website.