AirHint found the following cheapest return flights from Sydney (SYD) to Tongatapu (TBU) in September 2025 (see full year).

Return flights

09 Sep - 13 Sep	Qantas	direct
06 Sep - 09 Sep	Qantas	direct
02 Sep - 09 Sep	Qantas	direct
13 Sep - 27 Sep	Qantas
13 Sep - 20 Sep	Qantas	direct
13 Sep - 27 Sep	Qantas	direct
30 Sep - 07 Oct	Fiji Airways
30 Sep - 04 Oct	Qantas	direct
23 Sep - 11 Oct	Qantas	direct
30 Sep - 07 Oct	Qantas	direct
27 Sep - 04 Oct	Qantas	direct
05 Sep - 10 Sep	Fiji Airways
07 Sep - 10 Sep	Jetstar

Also check the deals for one-way flights from Sydney to Tongatapu in September.

The deals are updated regularly. The prices may go up as tickets are purchased by other travellers. Only the cheapest flights are offered. Select a price to book and secure these cheap prices.

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Cheapest return flights from Sydney to Tongatapu in September from 511€

Return flights