Elegant men's shoulder bag made of synthetic leather

What are the shoulder bags for men called?

Shoulder bags for men are referred to differently depending on their shape and how they are worn. Common names (and search terms) include:
Men's shoulder bag (very common general term)
Men's shoulder pouch (often used synonymously)
Men's crossbody bag / crossbody pouch (worn across the body)
Men's messenger bag (usually larger, "courier bag" style)
Men's body bag / sling bag (more compact, sporty look)
Men's bag (general term, also for handbags/clutches)

What are these bags called that you carry over the shoulder?

Bags that are carried over the shoulder are usually called:
Shoulder bag (a shoulder strap, classically over one shoulder)
Sling bag (over the shoulder, often at the side of the body)
Crossbody bag (with a long strap worn diagonally across the chest/back)
In everyday use, "shoulder bag" is often used as a general term, while "crossbody" describes the specific way of carrying. For men's models, search combinations like "shoulder bag men" and "crossbody bag men" are especially common.

How does one wear a shoulder bag for men?

A shoulder bag for men can be worn in three common ways – depending on style, comfort, and safety:
Crossbody (diagonally across the body)
Strap over the shoulder, bag rests at the side on the hip or chest
Advantage: secure hold, ideal in the city and while traveling
Tip: wear the bag more in front of the body when it is full (public transport, events)
Over one shoulder (classic)
Strap on one shoulder, bag hangs at the side
Advantage: quick access, casual look
Tip: strap not too long – otherwise the bag “swings” when walking
As a sling/body bag on the back or front
compact models across the chest or back
Advantage: sporty, light, perfect for essentials (phone, wallet, keys)
Adjust the strap length correctly:

The bag should sit so that you can easily reach inside – usually between waist and hip. Too low looks unbalanced and is impractical.

What is the difference between a shoulder bag and a crossbody bag?

The difference lies less in the "What" and more in the How:
Shoulder bag: typically carried on one shoulder; often has a shorter strap, classic look.
Crossbody bag: often carried with a longer strap and can be worn either over one shoulder or across the body.
In many shops, the terms are used interchangeably, but for SEO it makes sense to explain and use both:

"Crossbody bag (also shoulder bag/crossbody)" – this way you cover more search intentions.

What is another name for a men's bag?

"Men's bag" has several common alternatives – depending on whether you mean fashion, business, or everyday use:
Men's bag
Bag for men
Men's shoulder bag
Men's crossbody bag
Men's messenger bag
Men's sling bag / body bag
Men's handbag (less common, but searched for – often for compact models)

Are crossbody bags still fashionable?

Yes – Crossbody bags remain fashionable and are among the most popular bag styles for men because they are:
practical (hands free, quick access)
secure (close to the body, less “easy pick”)
versatile (streetwear, casual, even smart with leather)
available in many sizes: from mini crossbody (essentials) to messenger style (tablet/notebook)