A bank holiday seaside trip is now out of reach for one in five families because their incomes are so low, children's charity Barnardo's has warned.
Even cutting out all but the basic costs, the poorest families would have too little disposable income to be able to afford a city-to-coast visit, Barnardo's research showed.
The charity found that a family of four going, for example, from Aylesbury in Buckinghamshire to the Dorset resort of Bournemouth would need to fork out £172, with other city-to-coast trips, including London to Margate in Kent and Manchester to Blackpool, costing from £40 up to £127.
Barnardo's said that, as the minimum disposable income for the poorest 20% of families was £39, such trips would be unaffordable.
The charity's calculation was based on a family-of-four day trip to the seaside taking in the cost of the cheapest rail fare, a fish-and-chip meal, sun cream and ice-creams.
The cost did not include the cost of swimwear, towels, buckets and spades, armbands or inflatables.
These were the costs:
FROM TO COST
London Margate, Kent £95.70
Aylesbury Bournemouth £172.20
Birmingham Rhyl, North Wales £117.40
Leicester Skegness, Lincolnshire £127.40
York Scarborough £80.80
Durham Seaham, Co Durham £58.70
Manchester Blackpool £77.00
Bristol Weston-Super-Mare, Somerset £40.80
Barnardo's said: "Research shows that the poorest families have too little money to cover basic weekly living costs - let alone a trip to the beach.
"The incomes of the UK's poorest families have declined in recent years. They have been hit hard by a toxic mix of rising living costs and working and non-working benefits cuts. Welfare reform has included measures that break the link between benefits and inflation."
The charity said 20% of households currently bring in less than £423 a week and its calculations showed that - after covering basic living costs - a family of four on this income could not afford a seaside trip in any location surveyed.
Barnardo's chief executive Javed Khan said: "Family holidays have a special place in the childhood memory box, and every child deserves to have a day out once in a while, no matter what their circumstances.
"Whatever the weather, a day at the seaside with the family is a day to treasure. It is an opportunity for children to spend a healthy, happy time and experience a British cultural tradition - to play on the beach, splash in the sea and build sandcastles. It is an opportunity every child should enjoy.
"The Prime Minister has put family life at the heart of government and promoted the 'staycation'. Yet for hundreds of thousands of families struggling to make ends meet this weekend, a trip to the pier is but a pipe-dream."
A Government spokesman said: "This Government has taken action to help Britain's hard-working people be more financially secure through our tax and benefit changes.
"This includes increasing the tax-free personal allowance and freezing fuel duty and council tax.
"Our welfare reforms will further improve the lives of some of the poorest families in our communities with Universal Credit making three million households better off and lifting up to 250,000 children out of poverty.
"We continue to ensure there is a safety net in place, spending £94 billion a year on working age benefits to support millions of people who are on low incomes or unemployed so they can meet their basic needs."