I challenge Teltonika staff to reply (perhaps clarify/correct) this post, since Teltonika’s OWN documentation is confusing.
Scenario 1: Engineer arrives at site with replacement new Teltonika router (single modem, eSIM capable), and physcial SIM. Engineer has laptop to configure router via GUI. This scenario will FAIL - engineer will NOT be able to activate eSIM.
Scenario 2: Like scenarion 1, but engineer ALSO has a Wi-Fi hotspot with Ethernet port, or an ADDIITONAL Teltonika router with Ethernet port. This will SUCCEED, and the eSIM will be activated.
Why?
Teltonika use the common “consumer” interactive process for activating an eSIM, downloading the eSIM profile from an SM-DP+ (Subscription Manager Data Preparation) server. This is common for mobile phones, although “big brands” like Apple, Samsung and Google have a better experience where they host a proxy SM-DP+ server so eSIM providers can “push” the profile to the device IMSI (International Mobile Subscriber Identity). The choice Teltonika have made is pragmatic and I find no way to improve it. However…
The challenge
I advocate the use of dual-modem (not to be confused with dual-SIM) devices, such as the excellent RUTM52 (a PepLink killer if ever there was one!) However, most customers budget only stretch to single-modem dual-SIM devices. Since the device modem can, loginally, only “talk” to 1 SIM at a time (physical or eSIM), the eSIM absolutely MUST be set as “Default SIM” in order to recieve an eSIM profile. Do you see the “gotcha”, the “catch 22”, the condumrum here? Despite having a working physcial SIM, any single modem device CANNOT use that physical SIM to access the Internet in order to download the eSIM profile - the ONLY way the device can pull down the eSIM profile is to have it’s WAN Ethernet connected to another active Internet connection. But there could be another way…
Improvement
The engineer in scenario 1 above is probably thinking “Well, my laptop has internet (USB or Wi-Fi hotspot) so WHY can’t the Teltonika GUI use my laptop internet to download the eSIM profile?” Many factors, such as the eSIM provider’s server quering device parameters like IMSI and hardware signature, can cause the eSIM profile download to fail. Is there another way? Apparently…
…let’s consider how other manufacturers have addressed this challenge: Mikrotik, for example, ship their eSIM 5G devices WITH an active eSIM - the engineer can simply active a cheap 1-month subscription REMOTELY (no need to log into the GUI) as long as the serial number of the device is known. Immediately after purchase the eSIM in the Mikrotik device is now online, and if the engineer wishes to “push” a differnet eSIM onto the device then they can use SMS or web service to change the eSIM. This is a pragmatic and simple solution.
Summary and questions
Since Teltonika’s own documenation makes NO MENTION of the absolute requirement for WAN Ethernet connection (ESIM Configuration example - Teltonika Networks Wiki - as of 2025-07-23) to activate an eSIM on a single-modem device, this forum is filling up with frustrrated engineers asking questions about eSIM activation! Question 1: Would Teltonika staff please comment here to either correct me are verify my claims? Question 2: Do Teltonika have any plans to mimic other manufacturers such as Mikrotik, to make the eSIM “download” process simpler?
As regards the small footprint note “Note: - You will need an internet source to download the eSIM profile - Wired WAN or WiFi WAN”, this is confusing to many readers since they might understandably think “OK, I already have internet on my laptop that I use to access the Teltonika GUI…so surely I can download the eSIM.” Perhaps a HUGE banner at the top of the page would help set clear expectations? For example: “IMPORTANT: Your Teltonika router requires it’s wired Ethernet WAN port to be temporariliy connected to a 2nd Internet connection, such as another router or hotspot device, whilst it downloads the eSIM profile for the 1st time. Once the eSIM has been provisioned onto your router you can disconnect the wired WAN port.” (Most Teltonika routers, out of the box, do not provide facility for the Wi-Fi to act as a Wi-Fi client therefore only the wired Ethernet WAN port is suitable.)
Amazingly fast replies, superb answers, great plan! No wonder Lithuania is outperforming other countries in the Digital World Competitiveness Rankings - 
