International people-traffickers used a dinghy to transport illegal immigrants across the Channel, a court has heard.
Four Vietnamese men were smuggled into Walmer, Kent, in August 2018.
The criminal gang were unaware their operation was being recorded by undercover police officers, jurors at St Albans Crown Court were told.
Thomas Mason, 36, Hoa Thi Nguyen, 49, and Chi Tan Huynh, 41, all deny conspiracy to facilitate the illegal entry of foreign nationals into the UK.
Prosecutor Wayne Cleaver told the jury some immigrants were "so desperate" for asylum they were prepared to undertake what is a "treacherous journey".
He added: "They seldom do so without the connivance of criminal gangs whose primary interest is financial profit rather than any more noble motive."
Mr Mason of High Street, Eyeworth near Biggleswade, Ms Nguyen of Bisterne Avenue, Walthamstow, and her partner Mr Huynh of Pickford's Wharf, Hoxton, are accused of running their smuggling operation between 1 April and 3 August.
Mr Cleaver told the jury four others had already pleaded guilty to their role in the conspiracy:
- Nazmi Velia, 32, of Park Street Lane, St Albans
- Egert Kajaci, 35, of Turner Drive, Oxford
- Erald Gapi, 27, of Marine Tower, Deptford
- Wayne Lee, 46, of Grasmere Close, Watford
The court heard Mr Mason bought the boat with Velia on 26 June for £2,100 and launched it from the Kent coast repeatedly over the following weeks.
The prosecutor said these journeys "were intended to test the capabilities of the boat... and to investigate the best vantage points for landing people unobserved".
He added: "They did not know... they were being observed by a team of surveillance officers."
On 3 August at 01:00 BST the four migrants landed on the beach, and were seen getting into a car with Kajaci, the jury heard.
The trial continues.