Purchase a money belt from your local travel supply store to keep the coin secure. Money belts wrap around your waist under your clothes where you can keep valuable items such as money, travel documents, and other small items such as a coin. This prevents pickpockets from taking something in your wallet or from your bag.
Store the coin in shoes with a secret compartment where the sole can be removed. Certain brands, such as Keen's, often have removable soles in their shoes for storage of small items and money.
Sew a hidden pocket into your pants or jacket where you can store the coin. You may need to remove it when going through airport security, so make sure that it is still accessible.
Place the coin in your socks while traveling for safe storage from pickpockets.
Utilize the hotel's in-room or lobby safe if staying at a hotel. This will keep your coin concealed and safe throughout your trip without the worry of being mugged or having your room robbed.
Place the coin in a spare envelope and tape it somewhere secure in your hotel room. You could try the closet or underneath the trash can, as long as it is not in sight and you do not use the trash can during your stay.
