Your first month free.
Two if you keep your number.
For you and for whoever sent you here.
UNDO is a Belgian mobile operator running on the Orange network. From €4 a month, and whatever you don’t use rolls over to next month.
Zero Waste costs €4 a month, so that discount covers your first month exactly. Choose a larger plan and you get €4 off your bill.
You can order until 31 October 2026 inclusive.
What is UNDO?
A Belgian mobile operator. Small, but already more than 5,000 happy customers.
- The price
- From €4 a month — still the same price as last year, while rates went up elsewhere in the market this year. No contract, cancel any month, no hidden costs.
- The network
- The full Orange network, with 5G across Belgium. The same coverage as a large operator — you won’t notice a difference.
- What’s different
- Check what you actually used last month. For a lot of people 4 GB is plenty, and they pay every month for a bundle they never finish. At UNDO you pick what fits — and whatever you don’t use rolls over to next month.
- The trees
- For every plan we plant a tree in our own forest in Ibi Village, Congo, together with our local partner GI-AGRO. There are more than 20,000 by now.
This is where your tree grows — 10× faster than in Belgium. Planted with our local partner GI‑AGRO.
1 or 2 months free.
For both of you.
The discount isn’t deducted in one go. €4 comes off your bill each month — for two months if you keep your number.
one month
for two months
On Zero Waste at €4, that’s a free month. Or two.
Choose a larger plan and the same amount comes off your monthly bill. Whoever referred you gets the same discount — so make sure you have the mobile number of the person who sent you the link, you’ll need it at step 2.
Referring more than one person? The discounts stack. As an UNDO customer you can earn back up to €48 a year — on Zero Waste that’s a full year free.
Three steps.
One email.
No code to enter when you order. We sort the discount out afterwards.
You order online
Every plan counts. Identification via ITSME, eSIM in 30 seconds or a physical SIM within three working days.
You email us as soon as your number works
Send an email to support@undo.be with your mobile number and that of the person who referred you. Without that email we can’t apply the discount. You have until 30 November.
We take care of the rest
We check your connection and put the discount on both your next bills.
What do you pay when ordering?
If you take a new number, we ask for one month of the plan up front. If you keep your current number, we don’t. If you choose a physical SIM card, €5 shipping is added; with an eSIM it isn’t.
Everything you pay up front is settled on your first bill — together with your discount.
Four options.
One for you.
All on Orange 5G. Whatever you don’t use rolls over to next month. And for every plan we plant a tree.
UNDO Zero Waste
🌱With this offer: your first month free, or your first two if you keep your number.
- ✓4 GB data
- ✓400 mins & 400 texts
- ✓Rolls over: data, mins & texts
- ✓100% usable across Europe
- ✓1 tree planted
UNDO Rise
🍀With this offer: €4 off your bill, for two months if you keep your number.
- ✓8 GB data
- ✓800 mins & 800 texts
- ✓Rolls over: data, mins & texts
- ✓100% usable across Europe
- ✓1 tree planted
UNDO Boost
⚡With this offer: €4 off your bill, for two months if you keep your number.
- ✓30 GB data
- ✓Unlimited calls · 100 texts
- ✓Rolls over: data & texts
- ✓100% usable across Europe
- ✓1 tree planted
UNDO Wild
🌍With this offer: €4 off your bill, for two months if you keep your number.
- ✓40 GB data
- ✓Unlimited calls & texts
- ✓Rolls over: data
- ✓100% usable across Europe
- ✓1 tree every month
What customers
actually say.
“Extremely easy order prices and fast delivery. Activation went smoothly too. This was my second SIM. Have been using my first one for over a year now without issues.”
“I’m super confident with UNDO. The start took a bit longer, because my current number had to overtake from the old provider. But then was everything super fast, easy and working.”
“Quick and clear answers.”
Swipe for more reviews →
★ Read all reviewsYou might be
wondering…
If you’re joining
Does this apply to all plans?+
What do I pay when I order?+
In both cases €5 shipping is added if you choose a physical SIM card. It comes by parcel post, so you have it quickly. With an eSIM that €5 disappears.
Everything you pay up front is settled on your first bill. That bill shows the plan for the days already used, the plan for the new month, the shipping cost and any options. The discount from this offer is deducted straight from that first bill.
When will I see the discount?+
How do I claim the discount?+
Can I keep my number?+
Can I combine this with another promotion?+
How long does the offer run?+
If you’re referring
Who can refer someone?+
How many people can I refer?+
Do I have to do anything?+
Does my discount stand if the new customer leaves?+
Does my partner or housemate count?+
Your first month free. Then €4 a month.
Cancel any month. Every plan, one tree.
You can order until 31 October inclusive.
Then this offer is exactly for you: join through someone who already is a customer and you both get a discount. Don’t know anyone at UNDO? You can still order, just without the discount.
See the plans →