Relatives a mum-of-three are extremely concerned for her safety as they fear she may have been kidnapped.
Polish Karolina Bia Białkowska, 31, last contacted her sister by phone on August 8.
Her family say her phone and her social media have been inactive ever since.
Family and friends in both Hull and Poland are appealing for information and have checked all the local hospitals - but with no luck, HullLive reports.
Friend David Szwejda said: "I am very worried about her being missing as she could be in huge danger.
"She could have been kidnapped. She has never gone missing and from what I know she was doing something in gardening and I don't know her address. All I know is that she lived in Hull."
Her Polish relatives have reported her missing to Polish police and they have notified Humberside Police.
An appeal to find out what's happened to her has been published on a Polish Facebook page.
Karolina is said to have a tattoo on the left hand with a rose motif and tattoos with the names "Natalia" and "Victoria".
Humberside Police said they believe the woman has returned to her native country.
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They have urged relatives to contact them if they're still worried.
A spokesman said: "On Monday, August 16, we received a call from a concerned person about the safety of a woman on St Hilda Street in Hull.
"Officers attended the address and found that the woman had left the address and travelled overseas. Further checks will be made to ensure the woman is safe and well.
"We would always want to be called in relation to concerns for someone’s safety.
"Anyone who feels that someone is in danger or is worried about their safety can call us on our non-emergency number 101 and report their concerns. In an emergency always call 999."
