Android Phone: To change SIM 2 slot into WCDMA 3G Signal in dual SIM smarphones

Before trying to enable 3G signal in SIM 2 slot, we have to ensure that you smartphone manufacturer has availed this option for your phone.
You can see it in your phone specifications in phone manual or in some online websites.

What is WCDMA sim slot : 

In Dual SIM smartphone, only one SIM slot can be activated with high speed internet or WCDMA means (Wideband Code Division Multiple Access) . In some smartphones, it is interchangeable. But in some smartphones, primary sim is WCDMA / GSM and secondary sim is only for GSM (low speed internet  connection like 2G, EDGE)

dual sim slot switch 3G android

If it is clearly provided that  SIM 1 Slot is for WCDMA and SIM 2 Slot is of GSM type, then this procedure will not work most probably.
The only solution is to swap (Change the sim cards between the slots and use your desired 3G sim card in Primary SIM 1 slot.

Mostly dual SIM phones with high end specifications has this 3G Switching option and phones in low entry level market doesn’t have this switching option and they have primary SIM as 3G and Secondary SIM as 2G

If you hope that your phone specification has both slots can be used as 3G then we can proceed further.
Here we have to note that at same time we can’t enable 3G in both SIM slots.

How to set sim2 as wcdma:

So, If you want to convert Sim 2 Slot into 3G, you have to set SIM 1 slot as GSM, then set SIM 2 slot as WCDMA or 3G
Likewise if you try to convert SIM 1 as 3G, set SIM 2 slot as GSM first and then enable WCDMA in SIM 1 Slot.

It is better to plan accordingly in which SIM card, you are going to browse high speed internet mostly, then FIX that simcard as a Primary SIM card Slot.

Changing it often may result in confusion and it may also result  in unnecessary loss of talk time.

Will GSM sim work in WCDMA slot ?

Yes, GSM sim will work in WCDMA slot. But the internet browsing speed will be according to 2G speed of the network provider

To change from 2g to 3g on a dual sim lenovo smart phone ?

  1. Go to Settings → Mobile networks
  2. In network type choose WCDMA or 3G only
  3. Now your phone will show H or H+ or 3G signal if it is available in your location.