It may sound romantic, but they run the risk of ending up sick of the sight of one another; the current record stands at more than 50 hours and they're not allowed to disengage lips at any point – not to eat, or sleep or go to the bathroom.
It may celebrate love but it's more about endurance than passion or romance. For these steadfast couples the next two days or so is likely to feel very, very long indeed.
In this love match the rules are unforgiving: lips must be in contact at all times. There are no rest breaks. They must stand. They must stay awake.
No cushions or pillows are allowed. And perhaps cruelest of all – nappies (diapers) or incontinence pads of any kind are forbidden.
But these 9 couples believe their love is worth it, as is the prize: 100,000 baht ($3,300 US) in cash, two diamond rings to the same value and a free holiday.
The current Guinness Record stands at 50 hours, 25 minutes and 1 second. The organisers say the intention of this marathon is to focus attention on virtue.
"The reason for doing this is to celebrate Valentine's Day and also we would like to promote the love and warmth in the family," said Somporn Naksuetrong.
And who better to show that than the oldest contestants; 74 year old Panajeth Yomchinda and his 72 year old wife Suwanna. They've been married for 50 years.
"It reminds us of the old days when we were young," said Suwanna. "We want to relive our love from the past and see how we are now."
When the competition began they were just as keen as their younger rivals but they admit they are unlikely to make it beyond a few hours. Not so the title holders, who are back again. Before the start they showed fellow contestants how to go to the bathroom without breaking the rules.
Previously published at: http://www.indiatvnews.com/news/world/thai-couples-vie-for-guinness-world-record-for-longest-kiss-10578.html