Social distancing is placing added pressure on rescuers as crowds flock to beaches, the coastguard has warned.
A family of three had to be rescued after they became cut off by an incoming tide at Brancaster, Norfolk, on Wednesday afternoon.
A spokesman appealed for beachgoers to heed tide times after the Hunstanton rescue team recorded more than 30 incidents in two days.
"The coast is a dynamic environment - it will catch you out," he said.
The public has been urged to "think twice" before heading to beaches and country parks as councils fear a surge in visitors could result in a rise in coronavirus infections.
Beaches across England have been seeing high numbers of visitors, prompting concerns over social distancing.
Images posted on social media by the Hunstanton crew show a busy Brancaster beach in soaring midweek temperatures.
Tony Garbutt, HM Coastguard's senior coastal operations officer for north Norfolk, said the family had walked to the SS Vina wreck off Scolt Head Island at Brancaster - but had not anticipated the speed of the tide.
"The sea doesn't come in on a single wave. People think it arrives on a bus at a certain time," he said.
"It builds for two hours beforehand and continues for two hours after going out. It will move quicker than you can run.
"There are signs everywhere warning about them."
The team's callouts have included one to an elderly woman who suffered a broken hip in a fall.
"In the current climate we cannot be patrolling every approach to the sand flats," said Mr Garbutt.
"It's hard to rescue someone when you're social distancing."