We find one or two surprises. Coming across young children is one, playing with their mothers in a large, overcrowded cell.
There are seven kids in Phuket Prison, and more than 2000 inmates in a facility built to hold 750. We had been told how crowded a dormitory built to hold 300 prisoners can get.
''Get up in the middle of the night to go for a piss,'' our informant said. ''And the space probably will be filled when you get back.''
Having seen the dormitories now, we can swear that it would be true. There is row after row of men dressed only in shorts, shoulder to shoulder, hip to hip.
Near one huge dormitory - which still carries the sign ''Muslim Prayer Room,'' and that may have been what it was once - is the VIP dormitory.
This is where British prisoner Lee Aldhouse spends his nights, in a room for just 30 prisoners, cushy by comparison with the crowded dormitories.
Mr Aldhouse, undergoing trial for murder, won some special conditions when he was extradited from Britain in December.
Dormitory by dormitory, the prisoners are cleared out and carefully searched. Then their belongings are searched.
Phuket's Governor, Maitree Intusut, is leading this raid, saying to prisoners: ''Sorry to wake you up so early'' and being given a guided tour by Phuket Prison Commander Rapin Nichanon with other VIPs in tow, mostly wearing medical masks.
The smell is just as you'd expect. We didn't see any deodorant.
Because it's raining, the prisoners assemble in the mess hall instead of outdoors in the quadrangle.
In the women's section, the search of individuals is carried out by female officers with a slightly more delicate touch, but with gloves on.
Notes and love letters are found among the bedding and perused.
Through the bars and flywire screening, as one women's dormitory is cleared and searched, we see two children playing in the next dormitory.
It's more than a surprise. It's a bit of a shock. Still, the children play and appear to be healthy.
The governor stops and drops low to quiz a Russian woman, doing a year inside for theft.
For us, the door to the world outside opens after 90 minutes. The rain has stopped and we step through the gate, with relief.
Commander Rapin playfully locks the Governor inside. But like us, he'd rather not stay today, thank you.