The Garmin Fenix 8 and Apple Watch Ultra 2 are two of the best sports watches available, and two of my favorite devices, having worn them both for long stretches to track my marathon training in particular.

I ran the London Marathon 2025 wearing both watches, clocking 2:26:48. Both impressed me for GPS accuracy in particular, helping me to pace the race in the first half — the fact I went out too quickly and had to slow down was certainly my fault, not the watches!

Both watches are at the more expensive end of the sports watch spectrum, but the Apple Watch Ultra 2 is cheaper at $799 compared with $999 for the cheapest Fenix 8 model — the 47mm sapphire model I wore retails at $1,099.

Given the price and impressive specs on both watches, you expect a high level of performance. How did they perform at the London Marathon?

Precisão do GPS e como melhorá-la

The official marathon distance is 42.195km, but you usually have to run further than this distance in the race itself as you dodge around people and take a wider route around corners than the measured route.

That said, I was (mostly) able to stick to the blue lines on the road marking the fastest route around London on race day, and the Apple Watch’s overall distance of 42.26km is impressively close to the official distance.

The Garmin Fenix 8 measured 42.47km, which is still very good, and the GPS tracks of both watches are nearly identical.

That is aside from around Canary Wharf, which is where watches tend to go wrong in the London Marathon. Both watches were still pretty good here, but the Garmin had a slightly more accurate GPS track.

Overall I could pace the race using either watch and the lap alerts were closely aligned with the markers on the course, such was the high level of accuracy they offered thanks to the dual-band GPS available on both.

Precisão de RH na gestão de colaboradores e folha de pagamento

Durante uma corrida recente, não usei o meu monitor de frequência cardíaca com cinta peitoral, que geralmente utilizo durante os treinos para obter as leituras mais precisas. No entanto, em maratonas anteriores, já utilizei cintas peitorais e tenho uma boa noção de como deve ser a minha frequência cardíaca durante uma corrida longa.

Esperava ver um aumento gradual na frequência cardíaca à medida que o esforço aumentava, e foi exatamente isso que o meu rastreador de fitness mostrou no dia da prova. A frequência cardíaca subiu de forma constante, atingindo quase o máximo heart rate enquanto corria em direção à meta.

Durante a corrida, o Apple Watch Ultra 2 inicialmente teve dificuldades em monitorizar com precisão a frequência cardíaca, muitas vezes não indicar dados ou apresentar valores demasiado elevados. No entanto, após cerca de uma hora, começou a registar os dados de frequência cardíaca corretamente e aproximou-se bastante das leituras do meu Garmin durante o restante da prova.

Duração da bateria: dicas para melhorar o desempenho do dispositivo

I charged both watches overnight, so they were at 100% at the start of the day. I had the always-on screen enabled and put both in the most accurate and power-intensive GPS mode to track the run.

At 6 pm on Sunday, the Garmin Fenix 8 was at 84% and the Apple Watch Ultra 2 was at 67%, so the Garmin certainly wins the day on battery life.

I’d expect to be able to use the Fenix 8 for another week without charging, partly because I’ll be a lot less active than usual as I recover after the marathon.

The Apple Watch Ultra 2 would still easily last me two days while including a marathon, which is impressive for a smartwatch with such a large and bright screen. However, battery life is still an area where sports watches like the Fenix 8 have the edge.

veredicto: decisão ou julgamento final

Para além de alguns problemas iniciais de monitorização da frequência cardíaca com o Apple Watch Ultra 2, ambos os relógios tiveram um desempenho excecional durante a Maratona de Londres, especialmente na precisão do GPS em um percurso desafiante. O Garmin Fenix 8 continua a ser o meu relógio esportivo preferido, principalmente devido à sua impressionante autonomia de bateria, e também aprecio a análise detalhada que oferece para o treino de maratona. No dia da corrida, confiaria de forma segura em qualquer um dos relógios para me ajudar a completar com sucesso o prova.