Vanuatu dress code and security

Hello,

I'm heading to Vanuatu soon, and there are couple questions I cannot find answers yet.
I'm a young woman, traveling solo, interested in culture and nature, so I plan spend most of the time in outer islands.

1. I found different information about dress code. Some suggests cover top while swimming (bikini not acceptable), some says that it's important cover the legs. What would be the best "dress code" while walking and swimming in not so touristy places? Can I wear a knee length dress? What length is minimum? Can I swim with T-shorts, but legs uncovered?

2. I'm looking to cheap accommodations - dormitory in the city, bungalow in the islands. I'm wondering where I could leave most valuable items (like documents, cash) if I want go to the beach or for a walk? Are there anything like cupboards, which I could lock myself, or maybe something in "receptions", or it's best carry valuables with me all the time?

Appreciate any help.

1. Knee-length dress is certainly OK, ideally with shoulders covered, too.

2. I had no trouble leaving my valuables in my rooms in Vanuatu.
   Carrying things with you is also OK, but can become a dilemma when going swimming - leaving valuables in a heap on the beach is never/nowhere the best idea.

In Melanesian countries, it is the upper half of the legs, including knees, that need to be covered.
I haven't been to Vanuatu, but have many friends from there from my years living in Solomon Islands. I have never had a problem in Solomon Islands with sleeveless tops, and many local women wear them. However, in Vanuatu the traditional women's dress has short puffed sleeves.
For swimming, except in western-style resorts, you can wear long loose board shorts, or swimmers with a sarong tied around them, though in Solomon Islands I usually swim in a cotton dress or skirt and t-shirt.

The "mother hubbard" dress in Vanuatu did seem to be quite common. I noticed that women often had completely bare arms.

General rule I would think to be respectful would be cover up legs above knees, show no cleavage and that will about do it.

In the more populated 'western' areas - Vila and Santos you should be fine to wear a bikini at the hotel pool, anywhere else I would suggest you wear a t shirt and boardies when swimming or a long skirt and a t shirt if you are going off the two main islands (Efate and Santos). From my experience - on the outer islands (Pentecost, Ambae, Malekula) you can wear shorter clothes but note that you will probably be stared at and be the talk of the village (not always a good thing). If you are not sure - just pack a light cotton skirt (below the knee) and wear a t shirt.

I found the bungalows on the islands to be quite safe. Although, I did always take a pad lock with me and lock any valuables or just keep them in the bottom of my bag. Saying that, Vanuatu people are very friendly - I turned up on an island and a family took me in for about 5 days - gave me a spare 'house', and i ate with the villagers etc... - not unusual for this to happen!

When i was in Vanuatu, I was looking to the local women.
In Efate (out of Port Vila) they were usually wearing shorts and t-short while swimming, however young generation (18-20) was in bikinis as well.
In Tana I've seen a local woman swimming half naked, just with shorts together with her family, however beach wasn't crowded. Group of tourists in bikinis wasn't getting excessive attention either.
In Epi beach was empty, just kids in the water, and they didn't care about tourists in bikini.
Got rain in Pentecost, so there was no swimming.
Most of the time I was wearing a cotton shirt, firstly protecting my back from the sun. I was also wearing sarong when going out of the water.

Most of the time I was carrying my valet with me or leaving it in the room, there were no issues. There only danger to me belongings were rats in Tana, who stolen my sunscreen, but at least didn't tried do that with my passport.