Nine suspected migrants who landed at Pett Level Beach have been detained.
The group landed on the beach, near Winchelsea, on Tuesday morning (September 10).
All have been taken to Dover where they will be medically assessed before being transferred to immigration officials to be interviewed.
Sussex Police confirmed it assisted the Home Office with an operation at Winchelsea beach on Tuesday morning.
The nine detained near Winchelsea were a small percentage of the 86 UK-bound migrants intercepted attempting to cross the Channel on Tuesday – thought to be the highest number of people found on a single day.
Earlier on Tuesday morning, Border Force was alerted to two small boats travelling across the Channel towards the UK coast.
A Border Force cutter was deployed and intercepted the vessels.
Altogether 23 people, made up of males, females and claimed minors were transferred on to the cutter. One boat had 11 on board with the other carrying 12.
They were taken to Dover where they were medically assessed and found to be well before being transferred to immigration officials to be interviewed.
The Home Office said the migrants presented themselves as nationals of Iran, Afghanistan, Pakistan and the Philippines.
At Littlestone in Kent, 13 people who had crossed the Channel in a small boat and landed on shore were detained.
The migrants presented themselves as nationals of Iran, Iraq and Turkey.
Around midday, Border Force was alerted to a rigid-hulled inflatable boat (RHIB) near Dungeness, Kent, and Border Force vessel Hunter was sent to intercept and bring to boat back to Dover.
Of the 18 people on board, 14 presented themselves as Iranian nationals, three as Iraqi and one as Vietnamese.
Also around midday, Border Force was alerted to a RHIB in the English Channel and Border Force vessel Seeker was sent to intercept and bring the boat back to Dover.
There were 23 on board the boat, who identified as nationals of Iran and Ethiopia.
A Home Office spokesperson said: “Crossing the Channel in a small boat is a huge risk. The criminal gangs who perpetuate this are ruthless and do not care about loss of life.
“We are working closely at all levels with the French authorities to tackle this dangerous and illegal activity. In addition, Border Force cutters are patrolling the Channel and we have already deployed equipment including drones, CCTV and night vision goggles.
“Last month the Home Secretary and her French counterpart agreed to intensify joint action to tackle small boat crossings in the Channel. This includes drawing up an enhanced action plan to deploy more resources along the French coast to intercept and stop crossings.”
The Home Office Spokesman said it has returned more than 70 people who arrived illegally in small boats to Europe since January.