This is one of those questions that comes up periodically in invert keeping groups, and the short answer is: probably not, for most invertebrate keepers. But the longer answer involves understanding why, and what your actual options are if something goes wrong with your animals.
The insurance market for exotic pets in the UK
Exotic pet insurance exists in the UK. Companies like ExoticDirect and some general pet insurers offer policies that cover reptiles, birds, and small mammals. The policies typically cover veterinary fees, death from illness or accident, and sometimes theft. Some policies extend to "exotic pets" broadly, and technically an invertebrate is an exotic pet.
In practice, though, almost no UK insurance policy is designed with invertebrates in mind. The policies are written for animals that have established veterinary care pathways: bearded dragons, tortoises, parrots, snakes. Animals where a vet visit is a realistic option, a diagnosis is possible, and treatment might cost hundreds of pounds. Invertebrates do not fit this model well.
Why it usually does not make sense for inverts
The core problem is that veterinary care for invertebrates barely exists. There are a handful of vets in the UK who will look at an invertebrate, and even fewer who have genuine expertise in treating them. If your jumping spider has a problem, there is no realistic veterinary intervention in most cases. If your isopod colony is crashing, a vet visit is not the solution. The treatment for most invertebrate health problems is husbandry correction: fix the humidity, fix the substrate, fix the ventilation, fix the temperature. That is not something insurance covers.
The cost of most individual invertebrates is low relative to insurance premiums. A Porcellio scaber colony costs a few pounds to start. Even relatively expensive species like Cubaris morphs or large jumping spiders are in the range of fifteen to sixty pounds per animal. An annual insurance premium would likely cost more than replacing the animal, which makes the economics straightforward.
Then there is the issue of proving a claim. If a reptile dies, a vet can potentially do a post-mortem and determine cause of death. If an isopod colony declines over weeks due to a slow humidity problem, documenting that for an insurance claim would be extremely difficult. Insurers need a clear event and evidence. Invertebrate losses are rarely that clear-cut.
When it might be worth considering
If you keep high-value invertebrates, specifically expensive tarantulas, the calculation changes slightly. Some tarantula species sell for hundreds of pounds. A mature female Poecilotheria metallica or similar high-end species represents a genuine financial investment. If you have several expensive tarantulas, and your insurer will cover them under an exotic pet policy, it could be worth enquiring. Read the policy carefully and make sure invertebrates are not excluded.
Liability insurance is a different consideration. If you breed and sell animals, or if you do educational handling sessions at schools or events, public liability insurance protects you if someone has an allergic reaction, gets bitten, or claims injury. This is not about the animals' health but about your exposure to claims from other people. If you are running any kind of commercial activity with live animals, liability insurance is worth having regardless of the species.
What to do instead
For most invertebrate keepers, the best "insurance" is good husbandry. Learn the care requirements properly before buying. Set up the enclosure correctly. Monitor conditions. Build in redundancy: a spare heat mat in case one fails, backup substrate and food supplies, a second enclosure if you need to isolate an animal or split a colony.
Keep records of your colonies. If something goes wrong, knowing exactly when you last changed the substrate, what the temperature has been, and when you noticed a change helps you diagnose the problem. It also helps if you do end up talking to a more experienced keeper or one of the few invert-knowledgeable vets.
If you have a collection with real financial value, consider home contents insurance. Many home insurance policies cover personal possessions, and a collection of animals might fall under that depending on the policy wording. This would cover theft or damage (say, a power cut that kills temperature-dependent species) rather than illness. Check with your insurer whether live animals are covered. Most standard policies exclude them, but some will add them as named items.
The honest answer for the majority of UK invertebrate keepers is that insurance is not a practical option right now. The market has not caught up with the hobby. Veterinary infrastructure for invertebrates is minimal. Individual animal values are usually too low to justify premiums. The best protection for your animals is knowledge, good setup, and consistent care. None of that is insurable, but all of it is within your control.