Belgian teleco Mobile Vikings announced this week that it will begin accepting payment in BitCoin for SIM top-ups.
Their help and support page details:
After you’ve saved some bitcoins, you can use them to top up your SIM card or to buy a gift from Mobile Vikings. Just select the button ‘Top up now’ and choose ‘Bitcoin’. Next, you will be redirected to the platform of BitPay. You can now confirm the transaction via a QR code or by clicking the button ‘Pay with Bitcoin’. Within a few minutes, the transaction will be completed and you’ll receive the top-up.