The multi-coloured watch, which could potentially be a reference to the rainbow Pride flag, retails at £535,000 on luxury fashion site Farfetch.
The England captain's apparent symbolic gesture came after he was forced to abandon plans to wear a OneLove armband in England's opening game due to pressure from world governing body, FIFA.
Ahead of England's 6-2 win over Iran, the 29-year-old footballer led the squad from the team coach into the dressing-room at the Khalifa International Stadium and appeared to be sporting the colourful watch on his wrist.
Instagram account Insane Luxury Life shared a snap of Kane wearing the timepiece alongside the caption: "The captain of England @harrykane wears a rare @rolex Daytona 'Rainbow' 116595RBOW in 18k rose gold, one of the most sought after pieces on market."
Seven European nations competing at the World Cup – including Germany, England and Wales – planned to wear OneLove anti-discrimination armbands during the tournament, but were dissuaded from doing so following the threat of sporting sanctions from FIFA.
The band contains the rainbow colours associated with the Pride flag and had been set to be a strong statement in Qatar, a country which criminalises same-sex relationships.
On Monday Kane instead wore FIFA’s ‘No discrimination’ armband, which is not rainbow coloured.
The Tottenham striker had previously sported the OneLove armband in UEFA matches this season after the participating nations were given permission but he was unable to do so at the Khalifa International Stadium.
Watch: BBC's Alex Scott wears OneLove armband during World Cup coverage
“We’re disappointed,” he said after the match. “We wanted to wear it, that decision was taken out of my hands. I turned up to the stadium with the armband that I wore and I was told I had to wear that.
“Look, it’s out of our control as players. I’m sure the FA and FIFA will continue those discussions but most importantly today we focused on the game and got a great result.
“You’ve seen over the last five years we’ve made a stand as a squad and we’ll continue to do that as much as we can. We took the knee today as well but sometimes these decisions aren’t up to us and that’s the bottom line.”
Despite not being able to wear the armband, England manager Gareth Southgate has not ruled out his team making a gesture to highlight human rights concerns in Qatar, as other nations have, but says they will not be pressured into doing so.
The German team covered their mouths for the team photo before their opening World Cup match against Japan on Wednesday, while the Australia squad released a video highlighting issues in the host country.
Earlier this week, former Lioness Alex Scott was praised for wearing the OneLove armband on air as she presented the BBC’s coverage of the England game in Doha.
Pride in Football, which represents LGBT+ fan groups in the UK, wrote on Twitter: “England may not be wearing the #OneLove armband, but @AlexScott is right now on BBC.
“This is more than just LGBTQ+ rights, this is Human Rights.”
Additional reporting PA.