I have seen a number of discussions here and at other places asking for information on tackle shops in Bali. Some of the replies have not been the best, so thought I would give a resident's perspective.
I am a keen fisherman who has lived in Bali for years.
Unless convenience is the key factor, I would advise avoiding the tackle shops in Kuta, including the one that has been recommended here more than once. Prices are relatively high, and the quality not so crash hot.
I would highly recommend either:
Jaya Pancing (on Jalan Ngurah Rai bypass, just to the north of the BIMC Clinic but before the bridge), Tel: 0361 766598. The owner Pak Irianjaya is a fine fisherman, speaks good English and is helpful. This is still convenient for anyone staying in Kuta/Legian etc - just a 10 minute cab ride.
Puri Pancing is the best tackle shop in Bali: Jl. Diponegoro No 127 Denpasar (very close to the junction of Diponegoro and Teuku Umar), Tel: 0361-224858. Extremely professional set up, but for those in a hurry, a lot less convenient than Jaya Pancing. You can see them at puripancing dot com.
I hope that is helpful.