Related Fetishes
There are a number of other fetishes that use bondage clothing. This page is mostly intended to help you along if you have interest in those, and doesn't aim to be anywhere near complete. By following the links, you can find more pages in their links sections.
Note that I don't have experience with the listed companies, so I can't say anything about quality or service.

If you want to contribute a link, remember that I'm not interested in making exhaustive listings, but of course I might squeeze one in that is especially interesting / applicable. Other themes that are related to overalls or locking clothing are welcome too.

Jump to one of the following subsections:



Adult Babies

 playsuit of Privatina.de
Part of the Adult Baby/Diaper Lover community is also interested in bondage, e.g. to be forced to wear diapers. So you can find locking panties, blanket sleepers, sleeping bags, childish clothes (under which overalls and shortalls), harness with reins, etc.
Interesting shops include: Photos/Videos: Non-commercial pages:
Unluckily a number of my favorite sites have since shut down, and I don't want to link to blogs who only reblog or violate copyright, but here are some:

Wetting

 Not only (adult) babies pee in their pants: it might happen to adult women too, either as an accident, or because it's a fetish. Clothing that is difficult to take off makes accidents more likely. Sometimes people will even lock clothing to force the wearer to have 'accidents'.

Crossdressing

 Man locked in a dress
Sometimes male Adult Babies are also forced to cross dress, as little girls (sissies). Whenever cross dressing is involuntary, it might involve clothing that can't be removed by the wearer. (Either locked, buttoned in the back, restrained hands, ...) Similar areas where this happens are forced feminisation and petticoat punishment.
A number of fetish shoe suppliers also sell high-heeled shoes and boots with locking straps in man sizes.
And of course locking footwear and back-buttoning clothes work equally well on a 'natural' woman. LOL, I had named this section 'Cross dressing' before, but of course that means something other than I mean; perhaps unless you get cross from being crossdressed against your will ;-)

Back-Buttoning clothes

 Clothes that button up/down/in/at the back are very hard to take off yourself, especially if they are close-fitting.

Corsets

 a Locking Corset from Wasp Creations
For cross dressers they're used to get a more feminine shape, but of corsets have of course been pieces of constraining clothing for centuries. With laces and knots at the back, they're somewhat hard to free yourself from anyhow, but there are also locking variants.
In past centuries, when wearing corsets was normal for the higher classes, girls who had just started wearing their stays at night, sometimes had the tendency to loose them. Several measures were taken to prevent them from doing that, like locking belts, binding the hands, etc. Corsets also give a good attaching point for posture-enhancing shoulder straps and the like.
Apart from the normal corsets around the waist, there are also corsets for neck, arms and legs, and corset dresses available.

Chastity Belts

 locking metal underwear locking chastity corset Front locking chastity corset Back
Another piece of 'clothing' that has been around for centuries, is the chastity belt. According to the stories, crusaders locked their wives in metal panties to preserve their chastity, while they were off to war.
Nowadays it's mostly the fetish scene that reinvented them, but there are also parents wanting to keep their children chaste, either to be a virgin at their marriage, and/or to prevent masturbation. This was particularly common around 100 years ago, when masturbation was considered a serious health risk.
There even are a few rape-prevention devices that are similar, and some women wear chastity belts for that purpose.
Apart from chastity belts, there are also chastity bra's, connected sets and even chastity corsets. Some corsets also have a chastity strap attached.

Locking Jewelry

 Locking jewelry from sm-factory.de
There can be a thin line between jewelry and fetters. Jewelry that needs a special tool to open, and perhaps even can be connected into inconspicuous bondage.

Psychiatry

 Locking straightjacket     Butterfly romper
To restrain violent or self-violating persons, the psychiatry has a long history of using restraints and restraining clothing, like straightjackets.
Apart from clothing, there is a large assortment of straps to restrain a person, or keep him/her in bed. The locks that are used on these straps are often well-adaptable to clothing, and are fairly inconspicuous. (You can find pictures of the locks on the sites of Heetkamp and Segufix.)
The bondage scene has adopted the straightjacket enthusiastically, and made all kinds of variants in different materials, with attached shorts or skirt, etc.
Interesting companies include: Personal pages:

Geriatrics and Health Care

 Art-ex patient jumpsuit
Some elderly people, esp. with Alzheimer, have a tendency to undress at the wrong moments. For such undessers they make jumpsuits and such that are harder to take off. They are also called anti-strip suits. But for Alzheimer patients, out of sight is out of mind, so a zipper at the back or between the legs is often sufficient.
But sometimes you can find overalls in medical supplies shops that have restraining possibilities too, like the picture above from Ar-Tex, which features locking zippers to connect arms to torso and legs to each other.

Pony Play

 Scenes from pony play
Human ponies often wear restraints and harnesses that are locking. Sometimes even complete bodysuits. There are also some other animals that get 'impersonated', although you see those less often. Since animals don't need arms, those are often 'stored' out of the way, for instance in an armbinder or mittens. And then there's the bit, usually in a head harness.

Wool

 Actually almost all fetishes that involve clothing can be combined with bondage. One such is a wool fetish. Wearing many layers of wool, and not being able to take them off.

Rain gear

 It depends on the country, but especially in Scandinavian countries rain gear commonly consists of a jacket and overalls, or a jumpsuit. The company April Rain used to make great and colorful suits like that, but unluckily they are no longer in business. But Farmer Rain also has nice overalls.
Another company that I can't find anymore is the Icelandic Rain Dear; you can still see some pictures of their 2012 jumpsuit here.
Something a bit more towards bondage are waders with a built-in harness.
Jacob and Rubber Girl combine rubber rain gear with bondage on their website.

Patents

 Interesting enough, there are even some patents about locking / restraining clothing. Check out the following ones. You can find pictures if you scroll down to 'View PDF Images'. You might need to create a free account to see all pictures, which worked without hassle or fees for me. Of course you can also use the search engine on the top left to search for your own interests.
I also list the patent numbers, so you can find them on other patent sites etc.

The disadvantage of having two pages with links (this one and the Overalls links page), is that there are always sites that could go to either. So you're best off checking both pages.