This is general awareness, not veterinary guidance — your own vet, who knows your dog's age, health, and how much time it actually spends in shared spaces, is the right source for an actual vaccination and prevention plan. What follows is context for that conversation, not a substitute for it.

Why dense park use raises this specifically

A dog that shares the same grass, water, and general space with a large number of other dogs every day has meaningfully more exposure to a handful of specific things than one that mostly walks quieter routes. None of this means avoiding parks — it means the small extra vigilance is worth it for how much a dog gets out of using them regularly.

The named risks worth knowing exist

Kennel cough spreads easily anywhere dogs mix in groups — parks, daycare, training classes — and is exactly the kind of thing worth asking your vet about if your dog is regularly around a lot of other dogs.

Core diseases covered by standard puppy and adult vaccination schedules matter more, not less, for a dog using busy shared spaces often — this is the baseline a vet will already have you on track for, worth simply keeping up to date.

Leptospirosis, spread via standing water and wildlife urine, is genuinely relevant to a city with as much fox and waterfowl activity in its parks as London has — worth a specific conversation with your vet about prevention.

Lungworm, spread via slugs and snails a dog might pick up incidentally while investigating grass or puddles, is a real and often underappreciated risk in the UK generally, and one owners are frequently surprised to learn about at all.

Why this is a conversation, not a checklist

None of the above translates into a fixed action list that applies the same way to every dog — a puppy, a senior dog, and a dog that practically lives at the local park all warrant a slightly different answer, and that's exactly the judgement a vet is positioned to make that a general list isn't.

The actual takeaway

Regular park use is worth the small extra layer of vigilance rather than a reason to avoid parks altogether — the walks, the space to run, and (for what it's worth) the chance to meet a character along the way are worth enough that "ask your vet what's worth covering for a dog that's out and about this much" is a much better answer than either ignoring the question or overreacting to it.