3G sim card is going to phrase out.

I would like to confirm whether the following steps is correct to check whether our sim card is 4G.

Go to Setting > Network & Internet > Mobile network > click "service provider name, ex: Celcom, Digi, etc* > Advanced > Preferred Network Type [choose 4G (recommended)] > then press back, inside Network settings page > click * Access Point Name* > click service provider 4g

If the above step appear having 4G selection then our sim card is 4G already?

Yes.
How old is your sim card? If issued in the last 5 years should be already 4g

5 years + so not sure is 3G or 4G sim card.

Then use your method. Put in phone set to 4g only

In majority android, press *#*#info#*#*

just look at your signal bar there.
if got 4G / LTE means its 4G-enabled sim already.

or technically, if your sim is 3-in-1 it should be 4G-enabled also.



or u can just simply change the simcard at nearest center. replacement sim confirmed is 4G-enabled.
some telco can just get replacement sim via kiosk, easy.

Mine is Nano sim so it is a 4G sim card right?

yes.

if u on the mobile data, should be can see 4G or LTE symbol at signal bar there.

4G start service around 2010. 3-in-1 sim card conform 4G ready. Make sure your plan came with 'FREE basic internet'

Big mini sim card from mid 2006 up to 3G only. This sim card plan if used with 4G phone come with pay-per-use bill shock

It is weird.

My parents and I switched to Tunetalk during November 2012. Yesterday I checked with their CS, both of them are 4G sim card but mine is not. I double check with different CS and both gave me the same result. Only they can check from their system.

They even told me that 4G sim card is Nano size. Mine is Nano sim. She added that what signal display when I use mobile data, I do and saw it was 3G signal then I need to change.

I Google online how to identify is 4G sim, one of it is look at whether is Nano sim card and also check the phone setting (I listed out in my original post).

So, a bit confuse here. I am staying away from my parents so hard for them to follow to check the steps coz they are not tech savvy person, only can do simple task from their phone. Since they are 4G already then ok, left mine need to change sim card.