Police said it was too soon to say who was behind the attacks, but added that they had ruled out international terrorism.
New Zealander Rob Tolich, who is Phuket, said the Friday morning bombings have targeted areas that are very popular with tourists on Friday nights.
He said the normally crowded party area is on edge this evening, and he's been told to stay inside his resort.
"I wouldn't want to be on Bangla Road or anywhere in central Patong tonight at all. I would consider that quite dangerous.
"You can sort of feel it in the air, and people on the street, things aren't exactly kosher."
Phuket is frequented by millions of European, Chinese and Thai tourists each year who come to swim in the warm, azure sea, party at the open air night clubs and explore tropical rainforests. The other towns hit are less prominent international destinations but still popular among Thais and many foreigners.
Even as police searched for suspects and fears of more bombs continued, locals said the explosions will be a blow to tourism, a critical source of income.
Governments including the New Zealand, US, Germany, Australia and Britain advised their citizens traveling in Thailand to take precautions.
A spokesman for the Ministry of Foreign Affairs and Trade (Mfat) said the New Zealand Embassy in Bangkok was in contact with the Thai authorities.
"There is no information at this stage to suggest any New Zealanders may have been affected."
He said as of this morning there were 512 New Zealanders registered on SafeTravel as being in Thailand.
"We are advising New Zealanders in Thailand to exercise a heightened degree of vigilance in public places, follow any instructions issued by the local authorities and monitor the media to stay informed of developments," the spokesman said.
New Zealanders who require consular assistance are being advised to contact the New Zealand Embassy in Bangkok.
Tourism suffered a temporary hit after a bomb blast ripped through a Bangkok shrine nearly a year ago, killing 20 people, mostly visitors from other Asian countries.
"This ruins business. Hotels, restaurants, tours, we were already suffering, but this, it's going to ruin our lives," said Hua Hin Adventure Tours guide Natsupa Dechapanya.
Natsupa raced from hotel to hotel visiting clients and warning them not to go outside, especially where people gather. She was also fielding cancellation calls, although she was staying away from her office, opposite a clock tower where Friday's bombs went off.
"I'm scared, it's bad," she said. "This is the first time this has happened in Hua Hin. We think of this as a safe town, but now everyone is fearful. We feel like we're not safe."
She said because the explosions happened hours apart, many "including herself" are worried about whether the attacks are over. And she said without any arrests, tension on city streets is palpable.
"Usually this is a friendly town, but today no one wants to look up. People don't want to look each other in the eyes," she said.
Thailand's economy has struggled since a 2014 military coup; investors grew wary and have stayed away, but tourists came back, even after last year's shrine bombing. More than 14 million people visited between January and May 2016, up from 12.5 million the year before, according to the Tourism Authority of Thailand. Almost four million of this year's tourists came from China and around 400,000 from the US.
Earlier attacks have been tied to political turmoil. Friday was a national holiday in Thailand marking the Queen's birthday, also Mother's Day. They came less than a week after voters approved a new, junta-backed constitution.
Sirasit Teimtontanin, a manager at City Beach Resort in Hua Hin, said one of Friday's explosions went off about 300 metres from the front door.
The resort's 50 guests were asked to stay inside, but Sirasit said by late morning, some were venturing out to the beach on a balmy day. Stores, shopping malls and movie theatres were closed. But aside from a heavy police presence, he said, his town seemed normal.
Nonetheless, he said he's very concerned about the impact of the bombings on tourism at Thailand's beach resorts. More than 15 rooms had been cancelled within hours Thursday.
"We've never had anything like this in our city," he said. "Thai tourists will understand the police have the situation under control, but I think European tourists might not be coming."
BLASTS DESIGNED TO MAIM
Bangkok Post reports the "double-tap" bomb explosions went off at Soi Bintabat, near the Fah Pah intersection.
Municipality police chief, Police Colonel Sutthichai Srisopacharoenrat, said 19 people were hurt.
"Of the 19 [wounded], three are in serious condition and seven of the injured are foreigners - four women and three men," he said. Two of the injured were reportedly British.
The papaya food cart vendor positioned at the front of the beer bar was rushed to hospital after the blast but died of her injuries.
Photos from the scene show police identifying shrapnel scattered about the street that had been packed into the bombs to maximise harm.
British tourist Mark Gainsford told the BBC he was at a nearby bar when the bombs exploded.
"I heard people shouting 'Bomb! Bomb!' but I didn't hear any blast," he said.
"I ran out to see if I could help. I saw eight to 10 people injured, on the floor. The police arrived very quickly."
In April, a British family was brutally beaten by a gang of Thai men as they left a bar in Hua Hin province.
SPATE OF ATTACKS
In a separate incident earlier on Thursday, a bomb exploded at a market in the southern Trang province in Thailand, injuring six people, police said. Police believe that explosion was related to a local dispute.
Thais voted less than a week ago in a referendum to adopt a military-backed constitution, the first test of Prime Minister Prayuth Chan-ocha at the ballot box since he seized power in a coup in May 2014.
Hua Hin is home to a palace for years frequented by Thailand's revered King Bhumibol Adulyadej, the world's longest reigning monarch.
The 88-year-old is currently receiving treatment in a Bangkok hospital for a myriad of health complications.
The blasts also come days before the one-year anniversary of the last major bombing in Thailand, an attack in the capital that killed 20 people on August 17, mostly foreign tourists.
The explosive was planted in a popular Hindu shrine in the capital and was the deadliest assault of its kind in recent history.
Thai authorities have accused two Uighur men from western China of the bombing. They have both denied involvement in the attack and their trial is set to begin later this month.
Thailand's military junta, which seized power in 2014 after a decade of at times deadly political unrest, has touted increased stability in the kingdom as a major accomplishment of its rule.
But the generals have been unable to quell a festering Islamic insurgency in the three most southern provinces - nearly 1000km away from Hua Hin.
The conflict, which is largely contained to the far south region, has blighted the kingdom for over a decade and left over 6500 people dead.
