5 guides, each rated 1 to 5 with the reason — and two lists per place, where you are comfortable and where to pay attention. Nowhere is called dangerous; the specific thing is what helps.
Extremely safe, including for solo travellers at night. Air quality can be poor in spring due to dust — check the index and consider a mask. Summers are hot and very humid with a monsoon in July.
Comfortable: Seoul
Itaewon — and Hongdae on a crowded Saturday, for crush rather than crime
Drink spiking in Itaewon, which is rare but reported
Extremely safe, including for women travelling alone and at night. The practical cautions are seasonal: typhoons hit this coast between July and September and occasionally close the airport, and the summer humidity is heavy. The beaches have lifeguards in season and swimming outside it is not supervised.
Comfortable: Haeundae · Gwangalli · Seomyeon · Nampo-dong · the metro late at night
swimming outside the flagged season — the beaches are patrolled in July and August and not otherwise
the drinking streets in Seomyeon in the small hours — loud, not threatening
typhoons between July and September — they hit this coast directly and shut the beaches and sometimes the trains
Very safe. Hallasan is a serious walk with fixed turnaround times enforced by rangers, the coastal rocks are slippery and the sea around them has currents, and the island gets typhoons in late summer that close the airport for days.
Comfortable: Jeju City · Seogwipo · the Olle trails · Seongsan · the beaches
Hallasan without checking the cut-off times — rangers turn people back and the summit trail closes in bad weather
the coastal rocks — volcanic, sharp, and slippery where the sea reaches them
typhoons in late summer — they close the airport, which is the busiest route in the world and hard to rebook
Very safe. The park is the hazard in the ordinary way: Ulsanbawi is stairs and exposure, the weather turns on the ridge, and rangers close trails in snow and in high fire risk. The autumn weekend crowds are genuinely enormous.
Comfortable: Sokcho · the park entrance · the cable car · Naksansa
Ulsanbawi in ice — it is eight hundred steps of exposed metal and stone
the autumn weekends — the busiest days in any Korean national park, and the buses queue for hours
the ridge weather — it turns fast and the huts book out months ahead
The ratings are this site's own, from the guides' authors and the corrections readers send in; they are not an index. Read the general advice in travel safety tips.