Gulf leaders congratulated Bahrain on Sunday as it prepared to celebrate National Day this week.
On Monday, the country will mark 48 years since its independence from the UK.
Bahrain typically celebrates the occasion over two days, although there are fireworks and special events throughout the month.
On Sunday, King Hamad issued a decree pardoning 269 Bahraini prisoners.
The UAE President, Sheikh Khalifa, sent a message of congratulations to King Hamad and the Bahraini Prime Minister, Prince Khalifa bin Salman Al Khalifa, on their country's National Day.
His congratulations were echoed by Sheikh Mohammed bin Rashid, the Vice President and Ruler of Dubai, and Sheikh Mohamed bin Zayed, Crown Prince of Abu Dhabi and Deputy Supreme Commander of the Armed Forces.
Saudi Arabia’s King Salman sent a congratulatory message to King Hamad and “expressed his sincere compliments and best wishes”.
King Salman highlighted “the distinguished fraternal relations between the two countries and their citizens", Saudi Arabia’s state news agency said.
He expressed the need to strengthen and develop relations between the two states.
Saudi Crown Prince Mohammed bin Salman also sent his best wishes to King Hamad.
The Kuwaiti Emir, Sheikh Sabah, said Manama had experienced significant changes under the current government.
“Bahrain has seen swift developments under King Hamad’s watch,” Sheikh Sabah said.
He wished the Gulf state "continued success and prosperity".
The UN also marked the occasion. Bahrain’s Permanent Mission to the world body held a reception last week at its headquarters in New York.
“This year’s celebrations coincide with many significant occasions, such as the 100th anniversary of the start of formal education in the kingdom,” said Bahrain’s ambassador to the UN, Jamal Al Rowaiei.
Mr Al Rowaiei said female participation in the “fields of higher education and future sciences” had increased over the years.
“Since the 1930s, Bahraini women have participated on an equal basis with men in municipal council elections," he said. "Women today hold 55 per cent of high positions in the country."
Bahrain “takes pride in its women’s outstanding achievements” Mr Al Rowaiei said.
He also congratulated the Bahraini football team for defeating Saudi Arabia in the Gulf Cup of Nations final last week.
“The kingdom of Bahrain is already witnessing a year of significant achievement,” he said.