Vajiralongkorn is protected by one of the most strictly enforced lèse majesté laws in the world. For many years, criticism of the king, queen, crown prince, and more recently, former kings, members of the royal family, and even their pets have been strictly prohibited. Violations carry large fines and prison sentences of up to 35 years. However, Vajiralongkorn's private life continues to be a controversial subject of discussion in Thailand, although not publicly. In the 10 January 2002 edition of the Far Eastern Economic Review (FEER), an article appeared suggesting that Vajiralongkorn had business ties with then-Prime Minister Thaksin Shinawatra. An immediate ban was placed on distribution of the magazine, and the Thai government, citing a threat to national security, suspended the visas of FEER's two Thailand correspondents, Shawn Crispin and Rodney Tasker.
In 2002, The Economist wrote that "Vajiralongkorn is held in much less esteem (than the then-king Bhumibol). Bangkok gossips like to swap tales of his lurid personal life ... Besides, no successor, however worthy, can hope to equal the stature King Bhumibol has attained after 64 years on the throne." This issue of The Economist was banned in Thailand. In 2010, another issue of The Economist, also not distributed in Thailand, said that Vajiralongkorn was "widely loathed and feared" and "unpredictable to the point of eccentricity", while the online journal Asia Sentinel said that he was "regarded as erratic and virtually incapable of ruling"; the journal was blocked shortly thereafter. In a leaked diplomatic cable, senior Singaporean foreign ministry official Bilahari Kausikan said that Vajiralongkorn had a gambling habit partly funded by exiled former prime minister Thaksin Shinawatra.
On 12 November 2009, a home video was released to WikiLeaks, showing Vajiralongkorn casually dressed and Princess Srirasmi Suwadee wearing only a G-string, all the while being attended to by several formally dressed servants, celebrating the birthday of the prince's poodle, Air Chief Marshal Fufu. Part of this video was broadcast on the programme Foreign Correspondent, on the Australian ABC channel on 13 April 2010, as part of a half-hour documentary critical of the royal family of Thailand.
On 19 January 2009, Harry Nicolaides, an Australian national, was sentenced to three years in prison for self-publishing a fictional book deemed to have violated lèse majesté. The offending passage alluded to rumours that "if the prince fell in love with one of his minor wives and she betrayed him, she and her family would disappear with their name, familial lineage and all vestiges of their existence expunged forever". Nicolaides was later pardoned by the king. Nicolaides later stated that "it's entirely fiction from cover to cover".
In August 2011, the German judicial authorities in Munich impounded a Boeing 737 aircraft, one of two belonging to Crown Prince Vajiralongkorn. Administrators seized the aircraft because of a 20-year-old Thai government debt owed to a now-defunct German construction corporation for the Don Mueang Tollway, that had risen to some €30 million. German authorities, representing the corporation's interests in bankruptcy, stated the measure was a "last resort" in seeking repayment. The Thai government, which had not responded to German demands, called the move "highly inappropriate". On 1 August, Vajiralongkorn's office announced he would pay the deposit amounting to €20 million himself.
In November 2016, Manager Magazin published a report stating that the new king could be issued with an inheritance tax bill in excess of €3.5 billion. According to the report, the new King is domiciled in Bavaria where he owns two villas which makes him subject to local inheritance tax. On 16 May 2017, Thai officials warned Facebook after an online video was posted of the king wearing a crop top and with full view of his half sleeve tattoo.
