A crackdown on sham marriages by the immigration authorities netted 284 convictions last year - more than treble the 89 people convicted in 2012.
The dramatic stepping up of enforcement action coincided with far tougher penalties of up to 10 years in prison applying to these bogus unions.
Typically, marriages of convenience here involve foreign women whose "I do" really means "I do want to live in Singapore".
And for the Singaporean man, it is a case of "I do ...want some easy money" for taking part in the immigration scam. Middlemen who arrange these unions are also liable under the law.
The data for last year was provided by the Immigration and Checkpoints Authority (ICA) to The Straits Times last week.
The ICA said: "We take a serious view of individuals trying to circumvent our system by engaging in marriages of convenience to obtain immigration facilities."
The women in these marriages are usually from China, Vietnam or India, and want to enter Singapore or extend their stays here. The couples usually do not live together, and in some cases, do not even know each other's names.
Many go through middlemen, who could be Singaporeans or foreigners, with some working in syndicates.
The bogus bridegrooms can get paid thousands for their role in the scam. Meanwhile, the women look for jobs as masseuses and karaoke lounge hostesses, for example.
Last year was the first full year since tougher laws against sham marriage offences were enacted, to "send a strong deterrent signal and better enable the ICA to definitively deal with those who try to abuse the system" and to "stay ahead of the changing modus operandi of immigration offenders".
Previously, sham marriage cases came under Section 57(1)(k) of the Immigration Act, which deals with the making of false statements and carries a maximum penalty of a $4,000 fine and a one-year jail term.
The new laws, under Section 57C of the Act, deal with sham marriages entered into on or after Dec 19, 2012, and carry a maximum penalty of a $10,000 fine and a 10-year jail term.
Of the 284 cases last year, 124 of them came under Section 57C and 160 under Section 57(1)(k).
On its investigation techniques, the ICA referred only to "detailed background assessments and thorough investigations".
However, Tan See Swan & Co lawyer Tan Hee Joek suspects the ICA relies heavily on tip-offs.
He said: "It is quite difficult to know whether a marriage is genuine or sham unless they are alerted. After all, it is a very private matter between man and woman."
In the first four months of this year, the number of convictions fell to 56 - 23 under Section 57C and another 33 under Section 57(1)(k).
The figure is only 20 per cent of last year's total but for a period covering a third of the year.
But some observers note it might still be too early to say if the drop-off in numbers necessarily means the laws are having the intended deterrent effect.
Mr Tan said: "It takes time for the impact of sentencing effects to be felt, which might explain the 2013 spike.
"As time goes by and there are more reports of heavier penalties imposed on these kind of offences, more people may be deterred from sham marriages.
"But the profile of the male offenders who provide the supply are usually less-educated about the laws, and would risk doing this type of thing for the money."
Lawyer Sunil Sudheesan, from RHTLaw Taylor Wessing, added: "While it could be a case of them choosing not to engage for fear of the law, it could also be a case of a lot of people not getting caught."
ICA acknowledged the need to protect the sanctity of marriage, and said it works closely with the Manpower Ministry and Social and Family Development Ministry, as well as the Registry of Marriages to investigate cases.
In highlighting some cases, the ICA said it wished to send a strong deterrent message to potential abusers.
A spokesman said: "Getting involved in sham marriages for the money and/or gratification is not worth it as they will have criminal records for life."
