Although figures are not available, travel companies say such incidents are rampant.
Common items stolen include mobile phones, passports, cameras, wallets and purses.
Ms Jane Chang, 34, head of marketing communications at Chan Brothers Travel, says: "Theft is one of the more common crimes faced by Singaporeans abroad.
"They happen everywhere - from America to Europe to Asia - especially around tourist areas, town squares, bustling shopping districts and crowded trains."
Cities in Spain, Italy and France are most frequently brought up as places where tourists need to be on their guard.
Tour companies have plenty of stories.
Last year, a Singaporean man, while trying on a shirt in a factory outlet store in Madrid, placed his bag on the floor next to the display shelves. Within seconds, the bag - containing his passport and cash - was gone.
In June this year, a Singaporean woman was queuing for tax refunds at Barcelona Airport. While looking at her documents, she left her sling bag unzipped. She soon found her passport and purse missing from her bag.
Ms Alicia Seah, 51, director of public relations and communications at Dynasty Travel, says that from her understanding, about 300 pickpocket incidents are reported in the city of Barcelona every day.
"Singaporeans can be easy prey for predatory pickpockets, especially because coming from Singapore, a 'safe haven', we can sometimes take safety for granted.
"We might leave our bag on the floor or on unoccupied seats - unattended - and it can be an easy target for theft."
The agents note that pickpockets sometimes operate in syndicates, with one person distracting the victim while another commits the crime.
Minors are sometimes involved in these syndicates as well, notes Ms Chang.
"Victims are generally not as suspicious of children. And when caught, minors also cannot be held by the authorities," she adds.
Her advice? Do not keep all your valuables in one place. Sling your crossbody pouch in front of you and stay away from strangers and crowded areas.
Thankfully, there are also careful - or just lucky - travellers who have never had anything stolen from them.
Mr David Chang, 64, who owns a textiles company, has been travelling three or four times annually for the last 30 years, but has never been a victim of theft.
This, he says, is because he is extremely careful with his valuables.
He keeps his passport in the hotel safe and carries a photocopy of the document to identify himself.
The trousers he wears have deep pockets and he carries a thick wallet that cannot be easily removed.
Only half of his cash goes into his wallet. The rest is spread out in other pockets.
"I don't let strangers come close to me and I don't entertain random requests to fill in surveys or take photos."
He adds: "When travelling, it is easy to throw caution to the wind, especially when you see something exciting. But because you are in a foreign country, it is important to be vigilant at all times."
Guarding against pickpockets
•Never leave belongings unattended. Even at a cafe or restaurant, keep things on your lap or wrap the bag strap around your leg. Do not leave your bag at the side of the chair or at your feet. Get into the habit of looking behind you whenever you get up to leave a place.
•Separate your sources of money. Keep credit cards or cash in different places, preferably not all in one wallet, and on yourself. This way, even if something gets stolen, you still have alternatives to fall back on.
• Do not keep your wallet or purse in your back pocket. Keep it in your front pocket or in a properly zipped bag.
• Sling your crossbody pouches in front so that they are constantly in view.
• Avoid wearing expensive jewellery and watches. Keep your camera in a bag when you are not using it. Displaying expensive items makes you a target for thieves.
• Stay away from strangers and crowded areas. Do not give money to beggars or people on the street - you will need to take your wallet or purse out to do so.
In case of an emergency
• Jot down essential emergency phone numbers, such as those of the local police and the international contact number of your bank in case you need to cancel your cards.
• Scan and photocopy all important documents, such as travel documents, passport, driver's licence, visa, credit/debit cards and ATM cards. Keep a hard copy and e-mail the soft copy to yourself and someone else. This way, your documents will not go missing even if your bags do. In the event you lose your cards, it will be easier to get them replaced if you have a copy in hand.
• Buy comprehensive travel insurance. For example, United Overseas Bank (UOB) offers personal accident and travel inconvenience insurance coverage of up to $1 million when cardmembers buy air tickets with any UOB PRVI Miles card.
• Carry at least two credit cards while travelling. Leave one card in the hotel's safe deposit box in case of an emergency.
• Notify your bank of your travel destination prior to each trip and adjust your credit card limit accordingly. Following which, you can set mobile alerts for a pre-determined transaction limit so you will be notified each time a transaction hits above the pre-set limit.
• Write down your bank account number so that you can withdraw cash if there is a local branch at your destination.
• Find out your bank's policies on the replacement of cards. For example, how soon can a credit/debit/ATM card be replaced? Can you collect the replacement card at a local branch?
• Register overseas travel with the Ministry of Foreign Affairs to facilitate contact in case of an emergency.
If you are pickpocketed
If you are mugged, hand over your belongings and walk away. Cooperate with the assailant and do not try to do anything heroic. Your safety is most important.
If your credit/debit cards are stolen
Call the banks to cancel the stolen cards immediately to prevent transactions being made on the card. After that, file a police report at the closest police station.
For OCBC cards, the bank says a dispute form has to be filed if there are unauthorised transactions.
The disputed transactions will be investigated through the police report, dispute form and interview with the customer.
The bank will liaise with these parties to obtain more details and much of the investigation outcome will depend on the level of details provided by the police or customer.
Under normal circumstances, an investigation case involving stolen cards takes about seven working days to conclude.
If your passport is stolen
Make a police report in the foreign country and request a copy of the report or an acknowledgement slip or receipt.
If these are not available, get the report number, as well as the name and location of the police station.
Report the loss to the nearest Singapore overseas mission with the relevant supporting documents.
Under the Passports Act, the loss of a Singapore passport has to be reported within 14 days of the loss. Notwithstanding, it is strongly advised to report the loss immediately.
Collect a document of identity from the Singapore overseas mission, which will facilitate your return to Singapore.
Upon your return, apply for a replacement passport in person at the Immigration and Checkpoints Authority building.
If your identity card is stolen A police report is required as you are a victim of crime.
You must also report the loss to the Immigration and Checkpoints Authority and apply for a replacement in person.
$4,000 charged to my stolen credit cards within an hour
For two hours in Russia, I had no passport, no wallet and no credit cards.
I was pickpocketed in St Petersburg during a month-long trip from Istanbul to Dublin in April and May. And it ruined the whole trip.
On the morning of my second last day in the city, my travel companion and I had boarded a crowded public bus on our way to breakfast.
READ MORE HERE
•Sources: Dynasty Travel, Chan Brothers Travel, UOB, OCBC, DBS, Immigration and Checkpoints Authority