The Mangmoom card, it will start to be introduced on buses from October if the BMTA sticks to the MOT timeframe.

However, on the metro side the situation is bleaker than it appeared to be early this year.

None of the metro operators have started work yet to modify their ticketing platforms for the card. They see no advantage in doing so and will do nothing until forced. Blame the government for not forcing them. Some estimate that it will take 1 year to implement after the govt forces them to proceed.

I've said for many years that this is one of the fundamental flaws with the private concessionaire model used in Bangkok by the MOT. It really is stupid.

So keep those 3 cards (ARL, MRT & BTS) as you'll still be needing them for some time it seems!