Please be aware that Jakarta has multiple airports and that these results are for all airports serving the city.
The best month to fly between Jakarta and Semarang is October and the most expensive month to fly is June. (Average prices, based on 238816 datapoints.)
The best day to arrive at Jakarta is Monday and it would be best to avoid Friday, as prices are on average 6.31% higher than on Monday. (Average prices, based on 100709 datapoints.)
The cheapest airline flying from Jakarta to Semarang is Batik Air. They are 31% cheaper than Garuda Indonesia. (Average prices, based on 238829 datapoints.)
The best time to fly is at around 9. (Average prices, based on 258824 datapoints.)