I can't put it better than John W. McDMermott in his book "How to Get Lost and Found in the Cook Islands" which fed my passion for this Polynesian paradise
"Basically all you need to know or have in the Cook Islands is a sense of humour, a pair of old comfortable shorts, a passport and money"
But here's a bit more detail....
As long as you're staying no more than 31 days (90 days if you're a New Zealand citizen), your valid passport is the only entry permit you need, along with proof of onward journey, the means to support yourself while on the islands and somewhere to stay. THIS IS GRANTED ON ARRIVAL AND THERE IS NO FEE. And you can sort out the accommodation on arrival.
You can stay for up to five months more, but you'll need to extend your entry permit. New Zealanders can apply for a three month extension and other nationals for 31 days at a time. In both cases, you pay a fairly hefty fee for the privilege. Covid vaccination requirements for entry have now been dropped but you should still check the latest Cook Islands goverment requirements here.
Please also check any requirements of your own country with regard to Covid before travelling.
FULL DETAILS OF ALL TYPES OF VISA AND THE REQUIREMENTS AND ASSOCIATED FEES ARE HERE (government website)GETTING TO THE COOK ISLANDS
From June to September, the days are usually warm and sunny, but you might want a lightweight sweater or jacket at night because it can get chilly sometimes. From December to March, it's a bit hotter and more humid. It also rains a bit more, so maybe an umbrella will come in handy!
As a general rule, dress is casual except on Sunday (see Religion). I ran into the New Zealand High Commissioner one day in a cafe in town (as you do!) and his choice of attire was a Hawaiian style shirt and shorts!
Tourists are asked "to show consideration towards our customs and traditions by dressing appropriately in public places especially when visiting towns, churches or villages." It's suggested they carry something to cover up when wearing swimsuits if not on a beach or around a pool, and that "nude or topless sunbathing will cause offence”. Cook’s Island Bus won't allow people on board if they turn up in just a bikini or underwear.
The Cook Islanders are eastern Polynesians of the Maori Race who are British Subjects and New Zealand citizens. The language is Maori but English is almost everyone's second language. The islands are a democracy based on the British Model. Don't be surprised to see locals - male and female - wearing head dresses or eis, or maybe just a flower behind the ear (an indicator of marital status)
There's lots of it! The majority of islanders are Protestants of the Cook Islands Christian Church (CICC), inheritors of the London Missionary Society who brought Christianity to the islands in 1821. 43.1% of locals belong to the CICC, 16.7% are Roman Catholic and 8.7% Seventh Day Adventists. Locals wear their best clothes for church - women often in white, light dresses and men in shirt and tie. The churches are filled with glorious singing you have to hear to belive and you'll be amazed at the hospitality shown to church visitors
The New Zealand dollar is the unit of currency. It circulates alongside locally produced notes and coins which have the same value but are not legal tender outside the Cook Islands The $3 dollar note is a particularly popular souvenir. It features the iconic image of Ina and the Shark which has long been a part of Cook Islands folklore and legend.
Tourism generates nearly 80% of gross domestic product. Other mainstays are agricultural and financial services. For many years, black pearls were the main export, but the industry is currently in decline and fishing has now taken the top spot. The distinctive stamps and coins of the islands, which are much sought after by collectors, also generate a healthy income.
A bottle of Noni Juice makes a souvenir to dine out on (and with?) Locals will tell you it's really good for you...and it's a taste to remember! "Perfumes of Rarotonga" will help you remember your visit with a treat for the senses. Visit their store in town or go to their "factory" where everything is done by hand. Find out more.
And of course, stamps...a visit to the Philatelic bureau in town will overhwelm you with choice even if you're not a collector