Cheapest 20GB Mobile Plans — Any Network
The cheapest 20GB mobile plan across all networks is SB Unlimited 15 by lycamobile at $10.71/mo.
Not sure if it's worth switching?
Forward your current broadband bill to uploads@billhero.com.au — we'll check whether a cheaper plan is available and handle the switch for a $25 success fee.
Forward your bill20 Plans — sorted by price
Showing plans with 20–30GB data across all networks. Postpaid and prepaid only.
Prices validated: 26 July 2026
| Carrier | Plan | Data | Type | 5G | $/mo | Actions | |
|---|---|---|---|---|---|---|---|
 | SB Unlimited 15 | 20GB | Prepaid | No | $10.71 | Visit lycamobile | |
| SB Unlimited Plan XS | 30GB | Prepaid | No | $13.39 | Visit lycamobile | |
 | 30GB | 30GB | Postpaid | No | $15.00 | Switch — $25 | |
| 30GB Mobile | 30GB | Postpaid | Yes | $15.00 | Switch — $25 | |
| 30GB | 30GB | Postpaid | Yes | $15.00 | Switch — $25 | |
| Revolut 20 | 20GB | Prepaid | No | $15.00 | Visit lycamobile | |
 | 25GB | 25GB | Postpaid | Yes | $23.00 | Switch — $25 | |
 | Starter | 29GB | Prepaid | No | $23.90 | Visit yomojo | |
| Starter | 29GB | Prepaid | No | $23.90 | Visit yomojo | |
 | 20GB 5G SIM Plan | 20GB | Postpaid | Yes | $24.00 | Switch — $25 | |
 | 30GB | 30GB | Postpaid | No | $24.80 | Switch — $25 | |
 | 30GB | 30GB | Postpaid | Yes | $24.90 | Switch — $25 | |
| Starter | 29GB | Prepaid | No | $24.90 | Visit yomojo | |
 | Small Plan | 25GB | Postpaid | No | $25.00 | Switch — $25 | |
 | 25GB | 25GB | Postpaid | Yes | $25.00 | Switch — $25 | |
 | Small 25GB | 25GB | Postpaid | Yes | $25.00 | Switch — $25 | |
 | 28 Days Plan 22GB | 22GB | Postpaid | Yes | $26.79 | Switch — $25 | |
 | 22GB Data | 22GB | Prepaid | No | $26.79 | Visit coles-mobile | |
 | $25 SIM Plan | 25GB | Prepaid | Yes | $26.79 | Visit lebara | |
 | 29GB | 29GB | Prepaid | Yes | $29.00 | Visit ezee-mobile |
Bill Hero is an independent comparison service. We are paid by subscribers and concierge fees, not by carriers or retailers.
Frequently Asked Questions
What is the cheapest 20GB mobile plan across all networks?▾
SB Unlimited 15 by lycamobile at $10.71/mo is currently the cheapest 20GB plan across all networks. Prices are updated daily.
Should I choose postpaid or prepaid for a 20GB plan?▾
Postpaid plans typically include handset financing options and are billed monthly. Prepaid plans are pay-as-you-go — better for flexibility and no credit checks. Both are shown in the table above.
How often are mobile plan prices updated?▾
Bill Hero checks mobile plan data daily. All plans shown were validated within the last 24 hours. See the "Prices validated" date above the table for the most recent check.
Can I switch mobile plans without changing my number?▾
Yes. Mobile number portability (MNP) lets you keep your number when switching carriers or networks. The process usually takes 1–2 business days.
AutoMonitor
Turn on AutoMonitor. Your retailers send your bills straight to your Bill Hero address; we watch every bill for savings — automatically. $49/mo. Save money without even thinking about it.
Learn about AutoMonitor