The most common and most likely answer to this crossword clue is the 10 letter word ESPLANADES
I've seen this crossword clue in The Daily Telegraph
E
S
P
L
A
N
A
D
E
S
More clues leading to the result ESPLANADES
- Needs a slap when drunk walks by the sea
- Walks near sea and sand — please get dressed!
- English pals spread litter around walking areas
- Fresh sand, please, for use by the sea
- Guides plan a descent taking in waterside walks
- Walks by sea — and sleep as shattered
- Fresh sand, please, to make seaside features
- Sends a plea for restoring seaside walks
- Cultivating seeds around plot alongside first-class promenades
Buddy explains!

The straight part
We know that "Walks by sea" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case walks by sea = esplanades.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does ESPLANADES mean?
ESPLANADES noun- A clear space between a citadel and the nearest houses of the town.
- The glacis of the counterscarp, or the slope of the parapet of the covered way toward the country.
- A grass plat; a lawn.
- Any clear, level space used for public walks or drives; especially, a terrace by the seaside.