The International Longshoremen's Association (ILA) union and the United States Maritime Alliance (USMX) confirmed the deal on Thursday.
The tentative agreement is for a wage hike of around 62 per cent over six years, a source familiar with the matter told Reuters. The workers union had been seeking a 77 per cent raise while the employer group previously raised its offer to a nearly 50 per cent hike.
Both sides said in a statement that they would extend their master contract until January 15, 2025 to return to the bargaining table to negotiate all outstanding issues.
"Effective immediately, all current job actions will cease and all work covered by the Master Contract will resume," the statement said.
At least 45 container vessels that have been unable to unload were anchored outside the strike-hit East Coast and Gulf Coast ports by Wednesday, up from just three before the strike began on Sunday, according to Everstream Analytics.
The ILA launched the strike by 45,000 port workers, its first major work stoppage since 1977, on Tuesday after talks for a new six-year contract broke down.
US President Joe Biden's administration has sided with the union, putting pressure on the port employers to raise their offer to secure a deal and citing the shipping industry's bumper profits since the COVID-19 pandemic.
The administration repeatedly resisted calls from business trade groups and Republican lawmakers to use federal powers to halt the strike - a move that would undermine Democratic support among unions ahead of the November 5 presidential election.
The strike affected 36 ports including New York, Baltimore and Houston that handle a range of containerised goods.
Economists have said the port closures would not initially raise consumer prices because companies had accelerated shipments in recent months of key goods.
However, a prolonged stoppage would have eventually filtered through, with food prices likely to react first, according to Morgan Stanley economists.
"After the first week, we can expect some impact on perishable products like bananas, other fruits, seafood, and coffee, meaning fewer goods are reaching consumers, potentially driving up prices," said Tony Pelli, global practice director for security and resilience at BSI Americas.