How safe are mobile phone banking apps?

I’ve edited my text so it only shows a text has arrived. No other info.
Plus you need to sim lock the sim.
Or the sim can be taken out of the phone and put in a new one and they can get access.
On android go to Setting Notifications, Lock Screen, Format, show notifications but hide content,
Show notifications but hide content. (edited)

It's not the banking apps that are the issue here, it's the human factor.
You must secure your phone access... Even then you could be err, persuaded to give access !
As for the apps themselves , they are as secure as secure gets.

One of the problems that don't seem to have been mentioned here is that phones don't just represent a single attack vector, but several. So -

1. There's access to your phone via security holes (which can be a danger with older devices that no longer receive security updates) or malware

2. Access to your phone's contents, either via an exploit to circumvent PINs / fingerprints / slidepatterns, or there not being a suitable one set. Locks aren't as strong as you might think - I hacked my manager's phone (we're friends, it's okay) by following his finger grease pattern, my mate's 10yo (he's a little turd) hacked my phone by videoing me putting my 6-digit code in in slow-mo and following my steps.

3. Access to your texts. Lots of phones, by default, will show the content of a text on a lock screen (or on a companion device, like a paired smartwatch), making it easy to get OTP codes. This is something that should obviously be disabled.

4. Access to your SIM. If I steal your phone, I can bin the phone, keep the SIM, and put it into a new device. I can now receive texts sent to you, again giving me access to your OTPs. Some banks (and telecomms companies) also take the number of an inbound call to be unconfirmed ID for an inbound caller, and there's an extra danger there because the extra info they tend to ask for tends to be stuff kept near or alongside phones. A SIM lock can help mitigate this.

Personally, what I do is similar to what you're already doing, which is run two phones, using the second phone as my online banking phone, keeping it as locked down as possible, and also having it populated with a SIM which carries a number that's basically irrelevant to all my online banking stuff. The primary phone's locked down too, but that's all I can do, really. The rest is down to the bank's anti-fraud, which can be of varying quality.

I do agree with your approach. The mobile phone has now become a gateway to your whole life. Two factor authentication is a great idea, but when the 2FA text message comes through to your phone and appears on your lock screen, you don't even need access to your phone to get in.

But as the article shows, some are better than others. I knew some were weak, I didn't appreciate how weak.

Been using banking apps since they were first in beta.. Starling bank account holder since they first started more or less. Incredibly secure. I have fingerprint access and passcode access.

Lock screen is set to not show sensitive content so for banks I will get a notification but it won't show anything until I unlock my device.

It's always doubled up on authentication now. Love what banks have been doing these last few years to keep your money secure

it is safe as long as you lock your phone with finger print and secure PIN that no one can work out. without the phone being unlocked, they can't access your bank app, and when you log into the bank app, it needs finger print (if you have set it up on the bank app) or bank app PIN number. if you want to be really secure, then have a different PIN for the phone and the bank app.

also you should set up findmyphone to wipe data remotely when it is lost as well as locate it, so you can remove everything on the phone if it is stolen or is lost via your laptop/pc so there is nothing for the thief to steal.