Yes the EF 75-300mm III lens will fit and work on a 250D (called SL3 in N. America).
However, it's Canon's cheapest telephoto zoom and the reasons will probably become apparent once you start using it. It's lightly built, doesn't have particularly smooth focus/zoom rings, uses slower & noisier "micro motor" focus drive, doesn't have image stabilization and has pretty soft image quality at the longer focal lengths..
The EF-S 55-250mm IS STM lens is a better lens in almost every way. The main things are that it has faster, quieter autofocus STM (stepper motor) focus drive and IS (Image Stabilization) which is particularly helpful with telephoto lenses such as this. It uses Canon ET-63 matched lens hood, which is sold separately but recommended to protect the lens and improve images. It and the EF 75-300mm have pretty similar image quality between 70 and 100mm... but from 135mm and longer the EF-S 55-250mm is much sharper. It also is closer focusing, able to render higher magnification, slightly smaller and a little lighter in weight. One minor negative is that the 55-250mm uses a polycarbonate bayonet mount. I wish it were metal! (Note: There also is are versions of this lens without STM. They're older and the STM version seems to have the best image quality of the bunch.)
Compare image quality tests yourself at The-Digital-Picture website.
The primary "advantages" of the EF 75-300mm are it's 50mm additional focal length and low cost.
Canon EF 75-300mm f/4-5.6 III.... $199 new, (ET-60 lens hood, $29.95), widely avail. used, MPB.com has more copies of this lens than any other lens in their inventory: 154 to choose among, many under $100! (Note: There have been other versions of this lens with IS and faster USM focus drive. AFAIK, there's no difference optically and these were discontinued some time ago. They can be found used for under $200.)
Canon EF-S 55-250mm f/4-5.6 IS STM... $299 new. (ET-63 lens hood, $24.95), avail. used for $150-$180 (MPB.com).
There also are...
Canon EF 70-300mm f/4-5.6 IS USM II... $599. (ET-74B lens hood: $44.95) $359-$409 used at MPB.com.
Canon EF 70-300mm f/4-5.6 IS USM... discontinued first version. $174-$199 used at MPD.com.
Canon EF 70-300mm f/4-5.6 IS USM "L"... discontinued premium version, best image quality. Lens hood included, can optionally be fitted with Tripod Mounting Ring C ($180) . Lens is selling for $459-$754 used at MPB.com.
Canon EF 70-300mm f/4.5-5.6 IS USM "DO"... discontinued premium version using Diffractive Optics (DO) to allow for more compact size, but it is about the same weight as other lenses. Image quality is quite good. This was the most expensive 70-300mm when it was selling new: $1400. It is now selling for $224-$314 used at MPB.com.
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Alan Myers
San Jose, Calif., USA
"Walk softly and carry a big lens."
GEAR: 5DII, 7DII (x2), 7D(x2), EOS M5, some other cameras, various lenses & accessories
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