All Muslim women working in the malls in this east coast state must wear the tudung (head covering), there are separate payment counters for men and women in the supermarkets, and the call to prayer is proclaimed loudly five times a day to tell pious men to head to the mosque.
By decree, all shops in the state must display their shop names in Jawi, a Malay script based on Arabic lettering.
"Kelantan is a peaceful place to live in, though people say it is backward. There are no gambling dens. We are not rich, but we can still live comfortably. No one goes hungry here. If you go to the villages, the women are wearing gold bangles," said street vendor Ali Hussain, 36.
As if to confirm the city's Muslim character, a large sign at a prominent street corner proclaims "Kota Bharu Bandar Raya Islam" in Roman letters, or the "Islamic City of Kota Bharu". The word "bharu", or "new", uses an old Malay spelling.
Known widely in Malaysia as Serambi Makkah, or Mecca's Verandah, Kelantan wears religion on its sleeve. This is partly due to the wide influence of Parti Islam SeMalaysia (PAS).
But the east coast state today is roiled by whispers that PAS might lose in the May 9 general election, bringing the return of an old foe turned frenemy, Umno-led Barisan Nasional (BN).
PAS has ruled the poor state for much of the country's modern history since it gained independence. It ruled Kelantan for 18 years from 1959 to 1977, and has now done so for 28 years from 1990 until today.
As PAS sees it, it runs an honest and corruption-free government.
"Kelantan has shown a good model of government administration, governing with integrity," Kelantan PAS secretary Che Abdullah Mat Nawi told some 5,000 party faithfuls gathered at the state capital's football stadium last week.
The party's supporters said that although things might move more slowly in Kota Baru than in Kuala Lumpur, the situation is not so bad.
"It will be very hard for Umno to take Kelantan. PAS is like the air we breathe. Without PAS, there is no Kelantan," said a 43-year-old Kelantanese voter, who declined to be named.
Though PAS leaders often talk about raising an "Islamic state" in Kelantan and Malaysia, so far, its brand is quite separate from that of the Taleban.
The Chinese minority, who form less than 4 per cent of the 1.8 million Kelantanese, are largely left alone to run their businesses from motorcycle repair shops to restaurants to spectacle outlets.
Young Chinese women still don shorts and short-sleeved shirts to go out, and liquor is available at some shops.
A new 36-storey condominium project, with the fancy name of Troika Residences is coming up near the main stadium, with a one-bedroom unit being offered at RM326,000 (S$110,000) against RM400,000 in a typical Petaling Jaya suburb.
Supermarket brands Tesco, Giant and Pacific are available in Kota Baru, with most people ignoring the separate payment counters for men and women.
Air-conditioned restaurants with free Wi-Fi dot the sprawling city, with a cup of latte costing between RM5 and RM12, slightly cheaper than in Kuala Lumpur.
Still, the economic data shows why some Kelantanese are growing impatient with all the preachy talk of Islam.
Located far from the economic hub on the west coast linking Johor, Selangor and Penang, Kelantan had an economic output of RM21 billion in 2016 - the second smallest after Perlis among the 13 states. The economic output of Selangor - Malaysia's most industrialised state - was RM252 billion.
Additionally, annual per capita income in Kelantan was RM12,812 in 2016 - less than a third of the RM38,887 for the whole of Malaysia.
With limited jobs and options in Kelantan, analysts have estimated that up to 30 per cent of its voters work outside the state.
Outside a popular Kota Baru bazaar, batik seller Abdul Rahim said that when he opened his shop in 1990, PAS had just wrested Kelantan from Umno. Business was good for many years.
But today, things are so slow that he sits on a bench outside his shop trying not to doze off.
"I haven't sold anything for days. I am lucky that I have three children working in Kuala Lumpur who send me money. PAS as a government - they don't have the economic know-how or prowess to manage things. Everything is bent towards religion," the 78-year-old told The Straits Times.
Voters who work outside Kelantan want to replicate what they see in Kuala Lumpur, Petaling Jaya and Putrajaya in their home state.
The man leading BN's charge in Kelantan, Minister of International Trade and Industry Mustapa Mohamed, said part of the reason why Kelantan is not developed is that it is geographically disadvantaged, as it lacks resources such as infrastructure, water and electricity, unlike the west coast.
But he also cited "leadership mistakes" for this.
"Twenty-eight years under PAS, the lack of ideas, lack of innovation and resources - the state government is in no position to develop the state. That is why we believe in Umno. It is important for the people in Kelantan to vote for Barisan Nasional for their sake," Datuk Seri Mustapa told The Straits Times.
He said that BN would expand the airport and roads, increase investments in manufacturing, create more jobs and promote tourism in the state.
"Many Kelantan people would like to work in the state, but there are not many job opportunities. Kelantan is still lagging behind in terms of income and infrastructure."
Pollster Merdeka Center said recent surveys have shown that 55 per cent of Kelantan voters support BN today, compared with 35 per cent for PAS, and 10 per cent for Pakatan Harapan, the four-party opposition alliance.
Malay support for BN in Kelantan is estimated to have risen to 54 per cent, almost a 10 percentage point jump since 2013.
"There is a high likelihood that PAS will lose Kelantan. While they are not going to lose all 45 state seats - we think they will still hold 15 to 20 seats, the problem that they face is that they have a large number of marginal seats," said Merdeka Center's programme director Ibrahim Suffian.