Depending on where the olympiad is held, from what area a delegation travels to the olympiad, and which other countries are passed during the trip, it may be necessary to apply for appropariate visa. Visa applications can take a long time to process. Make enquiries early.
The IOI Host can provide an official Letter of Invitation, and sometimes also specific assistance for obtaining a visa.
Flight reservations, extra hotel days
Make flight reservations early. There may be other events going on at the same time that compete for seats.
If you arrive earlier (before the scheduled Arrival Day), or depart later (after the scheduled Departure Day), you will have to make your own hotel arrangements. Often, but not always, the IOI Host can be of assistance. For example, there might be a possibility to stay in the same hotel at a reduced rate.
Insurance and Vaccinations
The International Committee of the IOI supervises the preparations of each IOI. About half a year before the actual olympiad, they visit the site and inspect the preparations. They pay special attention to meals, sleeping accommodations, transportation, excursions, meeting facilities, safety and security, etc.
In spite of all the precautions, each delegation is advised to arrange for proper insurance, to cover for unforeseen expenses during the trip to/from the olympiad and during the olympiad itself, including unforeseen medical expenses.
At the olympiad, hundreds of people from all over the world get together for a week of close cooperation. You are advised to check the possible need for vaccinations. Contact your local medical advisor.
One of the sensible things you can do to reduce the risk of infection is to wash hands often: at least 5 times a day, with soap.
It has become a custom at some Olympiads, including the IOI, to exchange (small) gifts. Some people like this, others don't. Keep in mind that cultures vary as to their customs of gift giving and gift receiving. Dilemmas abound: when to give your gifts, whom to give a gift and whom not, how big a gift (size, value), when to open a gift, what to do if you cannot take it back home because you already have too much baggage (return it?, quietly throw it away?, give it to someone else?), what if you have no gift to give when you receive a gift, ...
At IOI, (small) gifts are part of the informal atmosphere. At some other Olympiads, gift exchanges have been abolished. However, IOI gift exchanges are not officially organized, nor are they especially discouraged or encouraged.
Be assured, not everyone is supposed to give a gift to everyone else. Do whatever you feel like.
What to Bring
Other things to keep in mind:
Bring business cards with your e-mail and WWW address.
Bring (English versions) of your national informatics olympiad tasks and solutions.
Do bring a gift for your guide, the person who escorts your delegation for an entire week.
Note that there may be restrictions on what goods you are allowed to bring into or take out of the area where the olympiad is hosted.
It may be advisable to register valuables (e.g. a laptop computer, digital video camera, etc.) upon leaving your home country. This can help avoid time-consuming discussions on your return trip.
Local Conditions: Weather, communications, currency
Each host will inform participants about local conditions, such as expected weather conditions, communication facilities (phone numbers, mobile phone coverage), and local currency, etc.