His Majesty the King said he was impressed by the unity among the Thai people who gathered to offer him their best wishes during his grand public audience.
The monarch also said he hoped the show of solidarity will provide inspiration for Thais to work together towards a prosperous future.
His Majesty delivered his speech as he appeared side by side with Her Majesty the Queen on the balcony of the Suddhaisavarya Prasad Throne Hall before a sea of yellow-clad jubilant Thais.
There were numerous chants of "Long Live the King" as the crowd waved yellow flags bearing the King's emblem.
"I and the Queen are delighted to see Thai people gather in unison to express their goodwill on the occasion of my coronation," the King said in a reply to a well-wishing message read by Prime Minister Prayut Chan-o-cha on behalf of the nation.
"The unity of all of you who are here to offer your best wishes and goodwill to me with sincerity is really impressive and gives me great pleasure. May the unity of you all who show goodwill to me be a positive sign for all sides to work together for the sake of the country's progress and prosperity.
"My thanks for the message of goodwill delivered by the prime minister on behalf of everyone and I would like to return my best wishes to you all. May you be happy and successful," His Majesty the King said.
Earlier, His Majesty granted an audience to Aziz Pitakkhumpol, the spiritual leader of Thailand's Muslims, religious leaders and members of the business community.
After the grand public audience, Their Majesties the King and Queen were driven to Chakri Maha Prasad Throne Hall where members of the diplomatic corps, foreign consuls and representatives of international organisations waited for an audience.
Singaporean ambassador Chua Siew San, as dean of the diplomatic corps, represented the gathering in congratulating the King.
"May this great Kingdom be blessed with abiding peace, prosperity and progress under Your Majesty's auspicious reign," said the ambassador.
In his reply, the King assured them that they will receive full support from the government and people.