Latias

[Cerris]

Is there any way to catch Latias before it runs away without a masterball?
Please reply.
Thanks in adv.

[Foguet]

Use Mean Look and it won't run away.

[Poryhedron]

Trapinch's Arena Trap won't work on it, but Wobbuffet's Shadow Tag will.

[Crazy Elf Boy]

Yeh Wobbufet's shadow tag works really well. Make sure you also have lots of Hyperpotions.

[Dark Dragonite]

I prefer having a fast mean looker, b-pass to an f-swiper, so yeah, probably Umby to anything but breeloom, probably scizor, grass/fighting against a flying/psychic = doom...

[Phraug]

Uhh, Lati@s is Dragon/Psychic, and doesn't know any flying moves when you encounter it. (Tho you still shouldn't send Breloom out against it -- all its damaging moves are Psychic!)

And I just checked, Umbreon is the only Pokemon that can learn both Mean Look and Baton Pass (including by breeding). However, Latias's moveset when you encounter it is {Psychic, Mist Ball, Refresh, Water Sport}, meaning Dark-types are immune to all its damaging moves, meaning you may as well just get one of the many Dark-type Pokemon that learn Mean Look that are much easier to get than Eevee. (Sableye, for example.) And EV train for speed.

[Cerris]

Trapinch's Arena Trap won't work on it, but Wobbuffet's Shadow Tag will.
"Thanks!"