The aquatic phase starts at snow melt, from February in the lowlands to June at higher altitudes, while egg-laying follows a few months later and can continue until August.
Some southern populations in Greece and Italy appear to stay aquatic most of the year and hibernate under water.
In the Apennine subspecies, I. a. apuana, two rounds of breeding and egg-laying in autumn and spring have been observed .

Breeding behaviour occurs mainly in the morning and at dawn.
Males perform a courtship display.
The male first places himself in front of the female, remains static for a while, then fans his tail to stimulate the female and wave pheromones towards her.
After leaning in and touching her snout, he creeps away, followed by the female.
When she touches the base of his tail with her snout, he releases a sperm packet (spermatophore) and blocks the female's path so she picks it up with her cloaca.
Several rounds of spermatophore deposition may follow.
Males frequently interfere with displays of rivals.
Experiments suggest that it is mainly male pheromones that trigger mating behaviour in females, while colour and other visual cues are less relevant.
In a breeding season, a male can produce more than 48 spermatophores, and offspring from one female usually have several fathers.

Females wrap their eggs in leaves of water plants for protection, preferring leaves closer to the surface where temperatures are higher.
Where no plants are available, they may also use leaf litter, dead wood or stones for egg deposition.
They can lay 70–390 eggs in a season, which are light grey-brown and 1.5–1.7 mm in diameter (2.5–3 mm including the jelly capsule).
Incubation time is longer under cold conditions, but larvae typically hatch after two to four weeks.
The larvae are benthic, staying in general close to the bottom of the water body.
Metamorphosis occurs after around three months, again depending on temperature, but some larvae overwinter and metamorphose only in the next year.
The aquatic phase starts at snow melt, from February in the lowlands to June at higher altitudes, while egg-laying follows a few months later and can continue until August. Some southern populations in Greece and Italy appear to stay aquatic most of the year and hibernate under water. In the Apennine subspecies, I. a. apuana, two rounds of breeding and egg-laying in autumn and spring have been observed .
Breeding behaviour occurs mainly in the morning and at dawn. Males perform a courtship display. The male first places himself in front of the female, remains static for a while, then fans his tail to stimulate the female and wave pheromones towards her. After leaning in and touching her snout, he creeps away, followed by the female. When she touches the base of his tail with her snout, he releases a sperm packet (spermatophore) and blocks the female's path so she picks it up with her cloaca. Several rounds of spermatophore deposition may follow. Males frequently interfere with displays of rivals. Experiments suggest that it is mainly male pheromones that trigger mating behaviour in females, while colour and other visual cues are less relevant. In a breeding season, a male can produce more than 48 spermatophores, and offspring from one female usually have several fathers.
Females wrap their eggs in leaves of water plants for protection, preferring leaves closer to the surface where temperatures are higher. Where no plants are available, they may also use leaf litter, dead wood or stones for egg deposition. They can lay 70–390 eggs in a season, which are light grey-brown and 1.5–1.7 mm in diameter (2.5–3 mm including the jelly capsule). Incubation time is longer under cold conditions, but larvae typically hatch after two to four weeks. The larvae are benthic, staying in general close to the bottom of the water body. Metamorphosis occurs after around three months, again depending on temperature, but some larvae overwinter and metamorphose only in the next year.
Alpine newt