The best passport to carry in Tonga's Vava'u islands is a blond-haired infant. The Customs officer's teenage daughter played with our son during the whole inwards clearance procedure then, with a broad smile, he stamped the paperwork for our yacht and ourselves, and gave the boy an affectionate chuck under the chin.
Every morning our son would be hoisted on my hip to visit the waterfront produce market and buy the fresh bananas, papaya and pineapple for breakfast. Our little blond boy always attracted the warmest caresses (and best prices) from the stall holders.
But soon after our arrival, our palangi (visitor) blond began turning a bilious shade of orange. We worried about hepatitis, and agonised over malaria. Maybe he had jaundice?
We perused the Dr Spock book that had advised us most of his brief life, but it offered no clues, so we walked up to the outpatients clinic at Neiafu Hospital.
In true Tongan style, the nurse reassured us with a broad smile.
"He eating a lot of papaya?" She asked. We nodded.
"That's what is causing it," she said. "It's the carotene."
He had, after all, been eating half a papaya for breakfast every day.
We're not the only southerners who seek the warmth and hospitality of the Vava'u islands with their babies.
Between July and November, huge humpback whales end their 6000km pilgrimage from Antarctica to give birth and loll about between the 60 islands which make up the archipelago, about 306km north of Nuku'alofa. A few stragglers are still enjoying the warm tropical waters, but it's a long swim between meals and they'll soon begin the long voyage to their frigid feeding grounds. On the way they'll pass by our island, Great Barrier, east of Auckland.
The RealTonga aeroplane descends to the warm air over the main island and lands between orderly files of tall coconut palms at Lupepau'u Airport.
"Welcome to Vava'u" the sign says and so do the wide white smiles of the local folk waiting to greet the plane.
Hospitality isn't an industry in Tonga — it's a tradition. Perhaps because the kingdom is the only Pacific country that wasn't colonised by a foreign power, so the Polynesian culture has remained intact and active.
To visit Vava'u is to become part of a village.
We're staying at Utungake village and within a few days we're like bona fide locals. People wave and call in greeting from their fale (house) doors, and gaggles of schoolkids practise their English on us.
We're directed to the special visitors pew at a local church and treated to a resounding harmony of three-part a-capella hymns and a soprano solo that could match Kiri te Kanawa's best efforts.
The sermon is mostly in Tongan with a bit of English added for our benefit.
But Sunday is sacrosanct, a day of rest with shops and businesses closed and the people at leisure.
Pigs of all sizes snuffle in the road side undergrowth or chomp on windfall coconuts and curious dogs wander up to sniff our legs.
In Neiafu town, the wonderfully ramshackle old market has been replaced by a concrete block building but the ladies selling their produce could almost be the same ones who were there last time.
"We live on an island about the same size as this," I explain to our taxi driver, Maka. "Except your roads are in better shape than ours."
He laughs politely.
"And we haven't got as many whales, pineapples, bananas ... or papaya."
Getting there: Air New Zealand and partner airline Virgin Australia fly from Auckland to Nuku'alofa, with up to eight flights per week.