you get both latias and latios after you beat pitfall valley.
In Pokemon Mystery Dungeon: Red Rescue Team Latias is found after you complete the 25th floor of Pitfall valley.
Latios : northern range latias: pitfall valley
either latios & latias or deoxys im not sure.
Rayquaza is on the 9th floor.
i do not know about blue rescue team but in red rescue team you have to buy southern island and do arescue next day the latios and latias event happens
Finish Pitfall Valley and recruit Latios Latias Finish Pitfall Valley and recruit Latios Latias
floor number 5
floor 20 of solar cave
If you've beaten Rayquaza and bought the Southern Island Friend Area, one early morning, Latios should zoom by your house, unlocking Northern Range. After beating Latios there, you unlock Southern Valley, where you rescue Latias. Then, both Pokemon join your team.
first you need to beat latios then you will gain excess to pitfall valley get to the end save latias then latias will ask to join your team pick yes and you have latias and latios. (you have to beat rayqwaza before this )and latios is at the end of northern range.
the last legendary in story mode is ryquaza and in free mode it is Latias
once you meet latias,latios will come kidnap her