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Old Sierra Leonean Leone (SLL) to Optimism (OP)

Convert old Sierra Leonean leones to Optimism at the live mid-market rate. Reverse: OP to SLL

The Old Sierra Leonean Leone is no longer in use

Old Sierra Leonean Leone (SLL) was replaced by the Sierra Leonean Leone (SLE) in 2022. For today’s money, convert SLE to OP.

1 Old Sierra Leonean Leone =

0.0003237 OP +1.62% today

1 SLL = 0.00032371 OP · 1 OP = 3,089.17 SLL

Mid-market rate, updated 03:49 UTC. Paid plans update as often as every 60 seconds. Get SLL→OP rates via API

SLL to OP over the last year

0.00020.0004Nov ’25Jan ’26Mar ’26May ’26Jul ’26Sep ’26
52-week high
0.00053319
52-week low
0.00005811
52-week average
0.00030170
Change over the year
+431.40%

Conversion tables

SLL to OP
SLL OP
1 SLL 0.0003237 OP
10 SLL 0.003237 OP
100 SLL 0.03237 OP
1,000 SLL 0.3237 OP
10,000 SLL 3.23711100 OP
50,000 SLL 16.18555500 OP
100,000 SLL 32.37111000 OP
OP to SLL
OP SLL
1 OP 3,089.17 SLL
10 OP 30,891.75 SLL
100 OP 308,917.45 SLL
1,000 OP 3,089,174.52 SLL
10,000 OP 30,891,745.24 SLL
50,000 OP 154,458,726.18 SLL
100,000 OP 308,917,452.36 SLL

Get SLL→OP rates via API

The live rate, the rate on any past day or a whole range, for OP and 170+ other currencies, as JSON. Free plan included. See the exchange rate API.

Get a free API key API documentation 
curl https://api.currencyapi.com/v3/latest \
  -G -d base_currency=SLL -d currencies=OP \
  -H "apikey: YOUR-API-KEY"

# the rate on a past day
curl https://api.currencyapi.com/v3/historical \
  -G -d base_currency=SLL -d currencies=OP \
  -d date=2025-10-04 \
  -H "apikey: YOUR-API-KEY"

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Questions about SLL to OP

How much is 1 SLL in OP?

1 Old Sierra Leonean Leone is 0.00032371 Optimism at the mid-market rate of 4 October 2026, 03:49 UTC, and 1 OP is 3,089.17 SLL.

What was the SLL to OP rate over the last year?

Over the last 52 weeks 1 SLL ranged from 0.00005811 to 0.00053319 OP, 0.0003017 OP on average.

Which exchange rate is this?

The mid-market rate: the midpoint between what currency markets pay and ask for SLL/OP, without the margin a bank or card issuer adds, so the rate you are charged is usually a little worse.