Leonard-Valter Tudor, 20, arrived in the UK on Friday and went to Yorkshire to meet a contact.
But the following day he was caught in the East Midlands, trying to steal £508 of goods from TK Maxx in Nottingham.
The father-of-one tried to use a foil-lined bag to interfere with the signals of security tags on the items.
He was arrested at the store and appeared on court on Monday, where he was detained in a young offenders institution for 16 weeks.
An accomplice managed to avoid arrest, Nottingham Live reported.
Sanjay Jerath, prosecuting, told the court: ‘In interview, the defendant said he landed in the country the day before. He went to an address in Doncaster intending to find some work.
‘He was approached by another Romanian man he doesn’t know. There was the suggestion of employment in Nottingham of taking items from a shop and accepts he was opening bags and taking items.
‘He had a foil lined bag and takes full responsibility for his action.’
District Judge Leo Pyle sent him to a young offenders’ institution for 16 weeks and ordered him to pay a £115 government surcharge.