You can ship a bicycle overseas in a variety of ways, but all include fitting the bicycle in a package of some sort, paying for postage and sending it to the correct destination. The packaging you'll use to ship the bicycle all depends on your personal preference. You can use a cardboard box, which can tear or disintegrate if it gets wet; a bicycle case, which can be pricey; or a bicycle bag, which is suitable for most people. All you have to do is get the bike into the packaging and send it off.
Take apart the bicycle. Use pliers and a set of socket wrenches -- an adjustable wrench works perfectly -- to remove the wheels, the saddle and the handlebars.
Place the bicycle and its components neatly into the packaging -- cardboard box, bicycle case or bicycle bag. If you're using a bicycle bag, pad the insides with cardboard, unless the bag is already padded. The cardboard will protect the bag from tearing and the bicycle from being damaged.
Seal the packaging. Use tape for the cardboard box and lots of it. The case and the bag can be sealed with padlocks.
Send the bicycle. You can use a variety of postage services to ship the bicycle, including Royal Mail, FedEx or UPS. Carefully indicate the destination to which the bicycle will be shipped. If you submit the wrong information, the bicycle may not land where you want it to. Place your name and address on the package so it will be returned to you if it can't be posted to its destination. You'll be charged a postage fee that depends mostly on the weight of the bicycle and the size of the package. Once you pay the fee, the postal service will take the bicycle, apply the postage and send off your package.
Depending on the bicycle's destination and the company you choose to ship your bike with, there may be an international shipping fee or an import fee. Sometimes the fee will be more than the bicycle is worth, as they range from £65 or lower to £390 and higher, in which case you can leave your bike behind and buy a new one when you arrive. You may also need to buy insurance to protect against loss or damage during transit.