Most travellers find the cheapest return airfare to Indonesia when booking during the month of February.
On average, from most locations, when planning your trip to Indonesia, try to book your flight in the region of 60 days in advance for the cheapest prices.
In general, booking your departure to Indonesia for a Tuesday represents the best deal on airfare. Try to avoid a Saturday departure to stay away from the highest prices.
On average you can find the best deals on plane tickets to Indonesia when looking for flights with evening departure times.