What is the best 4S eSIM promo code right now?

The best 4S eSIM promo code is TEE15. It gives Travel ESIM Expert readers 15% off 4S eSIM plans. This code works for All users and is valid for All plans, including country, regional and global plans.

We tested the code ourselves in September 2026 and confirmed that it works before payment on both the 4S eSIM website and app.

4S eSIM promo code details

What is 4S eSIM?

4S eSIM is a travel eSIM provider offering local, regional and global data plans.

We only came across 4S eSIM recently, so these were our first proper tests of the brand. From what we’ve seen so far, 4S eSIM is legit, the service worked for us in both the UAE and Taiwan and the promo code applied correctly at checkout.

One thing we already like about 4S eSIM is the flexibility. Instead of only giving you a few fixed plan options, 4S eSIM lets you adjust the validity and data amount on all of its plans. You can choose shorter or longer validity, from 1 day up to 365 days, and data options from 1 GB to unlimited data.

If you know exactly how much data you need, you can build something that fits your trip instead of overpaying for a plan that is too big or getting stuck with one that is too small.

How to use our 4S eSIM promo code

Using our 4S eSIM discount code is pretty straightforward. You can redeem the code through the 4S eSIM website or app. We tested both and the code worked in both places.

That said, we’d probably use the website next time. The app works, but it adds an extra step and we don’t think the app installation flow is as smooth as it could be yet.

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✓ Coupon verification process

How we verify 4S eSIM discount codes

4S eSIM coupon pages can include copied promo codes, temporary offers, expired discounts and exaggerated “up to” claims. For 4S eSIM, we only recommend TEE15 when we have checked it through a real checkout flow and confirmed that the discount works before payment.

Latest 4S eSIM code check: September 8th 2026

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We test the code at checkout

We check whether the 4S eSIM discount actually applies before payment, rather than relying on copied coupon lists.

2

We check the terms

We confirm whether the code applies to eligible 4S eSIM plans, destinations or promotion periods.

3

We keep a verification log

Every manual coupon check is recorded, so readers can see when the code was last confirmed as working.

4

We update broken codes

If a coupon stops working, changes discount or becomes restricted, we update the page instead of leaving outdated information live.

What we do not count as proof

• We do not treat a code as working just because it appears on another coupon site.
• We do not count vague “up to” claims unless the 4S eSIM plan, destination or terms are clear.
• We do not recommend codes that we know are expired, unclear or misleading.
• We do not count a code as better unless it produces a lower final checkout price before payment.

4S eSIM coupon verification log

✅ Code last confirmed: Sep 8, 2026 9:45 am

Manual checkout test: TEE15 applied successfully at 4S eSIM checkout before payment. Verified by Philip from UK. 5 consecutive manual checks since July 7, 2026.

Show verification history

Date	Code	Result	Verified by
Sep 8, 2026 9:45 am	TEE15	Working	Philip from UK
Sep 2, 2026 10:44 am	TEE15	Working	Philip from UK
Aug 24, 2026 9:30 am	TEE15	Working	Philip from UK
Aug 14, 2026 11:19 am	TEE15	Working	Estefanía from Portugal
Jul 7, 2026 8:28 am	TEE15	Working	Estefanía

Does the 4S eSIM promo code actually work?

Yes. We tested our 4S eSIM promo code TEE15 in September 2026 and confirmed that it applied correctly at checkout.

We tested it on both the 4S eSIM website and app. In both cases, the discount appeared before payment. The code gives you 15% off and is valid for All plans.

Our quick take on 4S eSIM

Let’s start with the good stuff:

4S eSIM worked for us in Korea, Taiwan, UAE. We installed and activated the eSIM, connected to local networks, used mobile data, tested hotspot and confirmed that our 4S eSIM promo code worked at checkout.

We also like the flexibility. 4S eSIM lets you adjust the validity and data amount on many plans, which is handy if you know exactly what you need. A 3 day city break, a month long trip and a longer remote work stay aren’t the same thing, so having more control over the plan can be useful.

Now for the part that we think needs improvement:

The app and website need a bit of love. The app is our least favorite part, mostly because it’s not an actual app. You can’t download it from the App Store or Google Play. Instead, you have to follow some steps to install a shortcut to the website.

Because of this, you also won’t find useful app features like notifications, proper data tracking and so on.

If you’ve used eSIMs before, you’ll probably notice this right away. If this is your first eSIM, the whole app situation might get confusing really quickly, in which case we’d recommend sticking to the website to make the purchase.

We think 4S could make the app more intuitive and user friendly.

As for the website, well, it’s not going to win any design awards. So in short, both the app and the website feel basic and lacking.

Our verdict: The 4S eSIM service is legit so far, the discount code works, the plan flexibility stands out and we’d use it again in other countries.

That said, there’s definitely room for improvement. With a few tweaks here and there, we think 4S eSIM can really up its game.

What has 4S eSIM been like in our test?

Our experience with 4S eSIM has been reliable so far. We’ve now tested the service in multiple countries and it has worked everywhere we’ve used it, without any major connection or usability problems.

Setup has generally been straightforward. Once installed, the eSIM has connected when we’ve arrived at our destination, with Data Roaming enabled on our iPhones.

The exact network experience varies by country. In the UAE, for example, our 4S eSIM could connect to both du and Etisalat and we received 5G on both networks. Etisalat performed considerably better during our testing, so having the ability to switch between networks was useful.

In Taiwan, the eSIM connected to Chunghwa Telecom. We only had access to one local network during that test, but speeds were good and the upload performance was particularly strong.

We’ve also been able to use hotspot without any problems during our testing.

Overall, we’d describe the 4S eSIM experience as solid rather than exceptional. It has been dependable everywhere we’ve tested it and we haven’t encountered any significant problems, but there also hasn’t been anything about the service itself that particularly stands out compared with other travel eSIMs we’ve tested.

That isn’t necessarily a bad thing. If you mainly want an eSIM that connects, provides reliable mobile data and doesn’t cause you any trouble, our experience with 4S eSIM has been positive so far. We’ll continue testing it in new destinations and update this review if that changes.

4S eSIM speed test results

Our 4S eSIM speed testing is still ongoing. This is what we’ve got so far:

Who should try 4S eSIM?

4S eSIM could be a good fit if you want wide destination coverage and like being able to personalize your plan.

It’s especially interesting if you already understand eSIMs and know roughly how much data you need. The mix and match style plan selection is useful, but it can also feel like a lot of options if you’re completely new to eSIMs.

Based on our experience so far, 4S eSIM is best for travelers who are comfortable with phone settings, QR codes and choosing their own data allowance.

It may also suit travelers who want a more flexible plan instead of a simple fixed package.

Who should choose another eSIM instead?

4S eSIM may not be the best choice if you want the simplest possible eSIM experience. If you’re on a short trip and just want to buy a fixed plan in 30 seconds without thinking too much, a more beginner friendly app may feel easier.

You may also prefer another provider if you want extras like travel perks, a very polished app or a super clear data tracking experience.

4S eSIM is data only, so it’s not the right choice if you need a travel eSIM with traditional calls or SMS.

Is 4S eSIM worth using?

Based on our tests so far, yes, 4S eSIM is worth trying, especially with our verified 4S eSIM promo code TEE15 that gives you an extra 15% off on any plan you want.

We can only personally recommend it based on our UAE and Taiwan experiences for now. It worked, connected to local networks, gave us 5G, supported hotspot and handled normal travel use.

That said, we do need more testing before we can compare it properly against other providers we’ve tested in more countries. So stay tuned, because our plan is to keep testing 4S eSIM everywhere we go and update this page as we collect more results.