Bananas can be picked in the banana plantation on Musa Point. By far the simplest way to get there is with an amulet of glory, which places you steps from the banana trees. Using baskets, which hold five bananas each, can significantly increase the number picked per hour.

Start out with 23 baskets in your inventory, with a charged amulet of glory and a ring of dueling equipped. Start picking bananas from the trees – conveniently, each one has exactly five bananas, which is the number needed to fill a basket. After picking each tree clean, fill your basket, and move on to the next one. When all 23 baskets are full, use your ring of dueling to teleport to Castle Wars, bank, and repeat. Each trip takes about 4 minutes, so you can bank over 325 bananas (5) per hour. These filled baskets will often sell for more than the bananas themselves, as they are used to protect curry trees in Farming.